AMDGPU/Docs: Make target naming consistent

[kzhuravl]

Summary

R600 Arch: Use Radeon HD XXXX Series
GCN Arch: Use GFXX

[t-tye]

LGTM

docs/AMDGPUUsage.rst

names from both the *Processor* and *Alternative Processor* can be used.
   .. table:: AMDGPU Processors
      :name: amdgpu-processors-table
 
      ========== =========== ============ ===== ======= ==================
      Processor  Alternative Target       dGPU/ Runtime Example
                 Processor   Triple       APU   Support Products
                             Architecture
      ========== =========== ============ ===== ======= ==================
-     **R600** [AMD-R6xx]_
+     **Radeon HD 2000/3000 Series (R600)** [AMD-RADEON-HD-2000-3000]_
      --------------------------------------------------------------------
      r600                   r600         dGPU
      r630                   r600         dGPU
      rs880                  r600         dGPU
      rv670                  r600         dGPU
-     **R700** [AMD-R7xx]_
+     **Radeon HD 4000 Series (R700)** [AMD-RADEON-HD-4000]_
      --------------------------------------------------------------------
      rv710                  r600         dGPU
      rv730                  r600         dGPU
      rv770                  r600         dGPU
-     **Evergreen** [AMD-Evergreen]_
+     **Radeon HD 5000 Series (Evergreen)** [AMD-RADEON-HD-5000]_
      --------------------------------------------------------------------
      cedar                  r600         dGPU
      redwood                r600         dGPU
      sumo                   r600         dGPU
      juniper                r600         dGPU
      cypress                r600         dGPU
-     **Northern Islands** [AMD-Cayman-Trinity]_
+     **Radeon HD 6000 Series (Northern Islands)** [AMD-RADEON-HD-6000]_
      --------------------------------------------------------------------
      barts                  r600         dGPU
      turks                  r600         dGPU
      caicos                 r600         dGPU
      cayman                 r600         dGPU
-     **GCN GFX6 (Southern Islands (SI))** [AMD-Souther-Islands]_
+     **GCN GFX6 (Southern Islands (SI))** [AMD-GCN-GFX6]_
      --------------------------------------------------------------------
      gfx600     - tahiti    amdgcn       dGPU
      gfx601     - pitcairn  amdgcn       dGPU
                 - verde
                 - oland
                 - hainan
-     **GCN GFX7 (Sea Islands (CI))** [AMD-Sea-Islands]_
+     **GCN GFX7 (Sea Islands (CI))** [AMD-GCN-GFX7]_
      --------------------------------------------------------------------
      gfx700     - bonaire   amdgcn       dGPU          - Radeon HD 7790
                                                        - Radeon HD 8770
                                                        - R7 260
                                                        - R7 260X
      \          - kaveri    amdgcn       APU           - A6-7000
                                                        - A6 Pro-7050B
                                                        - A8-7100
gfx703     - kabini    amdgcn       APU           - E1-2100
                 - mullins                              - E1-2200
                                                        - E1-2500
                                                        - E2-3000
                                                        - E2-3800
                                                        - A4-5000
                                                        - A4-5100
                                                        - A6-5200
                                                        - A4 Pro-3340B
-     **GCN GFX8 (Volcanic Islands (VI))** [AMD-Volcanic-Islands]_
+     **GCN GFX8 (Volcanic Islands (VI))** [AMD-GCN-GFX8]_
      --------------------------------------------------------------------
      gfx800     - iceland   amdgcn       dGPU          - FirePro S7150
                                                        - FirePro S7100
                                                        - FirePro W7100
                                                        - Radeon R285
                                                        - Radeon R9 380
                                                        - Radeon R9 385
                                                        - Mobile FirePro
gfx803     - fiji      amdgcn       dGPU  ROCm    - Radeon R9 Nano
                                                        - FirePro S9300x2
                                                        - Radeon Instinct MI8
      \          - polaris10 amdgcn       dGPU  ROCm    - Radeon RX 470
                                                        - Radeon RX 480
                                                        - Radeon Instinct MI6
      \          - polaris11 amdgcn       dGPU  ROCm    - Radeon RX 460
      gfx804                 amdgcn       dGPU          Same as gfx803
      gfx810     - stoney    amdgcn       APU
-     **GCN GFX9** [AMD-Vega]_
+     **GCN GFX9** [AMD-GCN-GFX9]_
      --------------------------------------------------------------------
      gfx900                 amdgcn       dGPU          - Radeon Vega
                                                          Frontier Edition
                                                        - Radeon RX Vega 56
                                                        - Radeon RX Vega 64
                                                        - Radeon RX Vega 64
                                                          Liquid
                                                        - Radeon Instinct MI25

 ---------
 
 AMDGPU backend has LLVM-MC based assembler which is currently in development.
 It supports AMDGCN GFX6-GFX8.
 
 This section describes general syntax for instructions and operands. For more
 information about instructions, their semantics and supported combinations of
 operands, refer to one of instruction set architecture manuals
-[AMD-Souther-Islands]_, [AMD-Sea-Islands]_, [AMD-Volcanic-Islands]_ and
-[AMD-Vega]_.
+[AMD-GCN-GFX6]_, [AMD-GCN-GFX7]_, [AMD-GCN-GFX8]_ and [AMD-GCN-GFX9]_.
 
 An instruction has the following syntax (register operands are normally
 comma-separated while extra operands are space-separated):
 
 *<opcode> <register_operand0>, ... <extra_operand0> ...*
 
 Operands
 ~~~~~~~~
hello_world:
      flat_store_dword v[1:2], v0
      s_endpgm
    .Lfunc_end0:
         .size   hello_world, .Lfunc_end0-hello_world
 
 Additional Documentation
 ========================
 
-.. [AMD-R6xx] `AMD R6xx shader ISA <http://developer.amd.com/wordpress/media/2012/10/R600_Instruction_Set_Architecture.pdf>`__
-.. [AMD-R7xx] `AMD R7xx shader ISA <http://developer.amd.com/wordpress/media/2012/10/R700-Family_Instruction_Set_Architecture.pdf>`__
-.. [AMD-Evergreen] `AMD Evergreen shader ISA <http://developer.amd.com/wordpress/media/2012/10/AMD_Evergreen-Family_Instruction_Set_Architecture.pdf>`__
-.. [AMD-Cayman-Trinity] `AMD Cayman/Trinity shader ISA <http://developer.amd.com/wordpress/media/2012/10/AMD_HD_6900_Series_Instruction_Set_Architecture.pdf>`__
-.. [AMD-Souther-Islands] `AMD Southern Islands Series ISA <http://developer.amd.com/wordpress/media/2012/12/AMD_Southern_Islands_Instruction_Set_Architecture.pdf>`__
-.. [AMD-Sea-Islands] `AMD Sea Islands Series ISA <http://developer.amd.com/wordpress/media/2013/07/AMD_Sea_Islands_Instruction_Set_Architecture.pdf>`_
-.. [AMD-Volcanic-Islands] `AMD GCN3 Instruction Set Architecture <http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_GCN3_Instruction_Set_Architecture_rev1.1.pdf>`__
-.. [AMD-Vega] `AMD "Vega" Instruction Set Architecture <http://developer.amd.com/wordpress/media/2013/12/Vega_Shader_ISA_28July2017.pdf>`__
+.. [AMD-RADEON-HD-2000-3000] `AMD R6xx shader ISA <http://developer.amd.com/wordpress/media/2012/10/R600_Instruction_Set_Architecture.pdf>`__
+.. [AMD-RADEON-HD-4000] `AMD R7xx shader ISA <http://developer.amd.com/wordpress/media/2012/10/R700-Family_Instruction_Set_Architecture.pdf>`__
+.. [AMD-RADEON-HD-5000] `AMD Evergreen shader ISA <http://developer.amd.com/wordpress/media/2012/10/AMD_Evergreen-Family_Instruction_Set_Architecture.pdf>`__
+.. [AMD-RADEON-HD-6000] `AMD Cayman/Trinity shader ISA <http://developer.amd.com/wordpress/media/2012/10/AMD_HD_6900_Series_Instruction_Set_Architecture.pdf>`__
+.. [AMD-GCN-GFX6] `AMD Southern Islands Series ISA <http://developer.amd.com/wordpress/media/2012/12/AMD_Southern_Islands_Instruction_Set_Architecture.pdf>`__
+.. [AMD-GCN-GFX7] `AMD Sea Islands Series ISA <http://developer.amd.com/wordpress/media/2013/07/AMD_Sea_Islands_Instruction_Set_Architecture.pdf>`_
+.. [AMD-GCN-GFX8] `AMD GCN3 Instruction Set Architecture <http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_GCN3_Instruction_Set_Architecture_rev1.1.pdf>`__
+.. [AMD-GCN-GFX9] `AMD "Vega" Instruction Set Architecture <http://developer.amd.com/wordpress/media/2013/12/Vega_Shader_ISA_28July2017.pdf>`__
 .. [AMD-OpenCL_Programming-Guide]  `AMD Accelerated Parallel Processing OpenCL Programming Guide <http://developer.amd.com/download/AMD_Accelerated_Parallel_Processing_OpenCL_Programming_Guide.pdf>`_
 .. [AMD-APP-SDK] `AMD Accelerated Parallel Processing APP SDK Documentation <http://developer.amd.com/tools/heterogeneous-computing/amd-accelerated-parallel-processing-app-sdk/documentation/>`__
 .. [AMD-ROCm] `ROCm: Open Platform for Development, Discovery and Education Around GPU Computing <http://gpuopen.com/compute-product/rocm/>`__
 .. [AMD-ROCm-github] `ROCm github <http://github.com/RadeonOpenCompute>`__
 .. [HSA] `Heterogeneous System Architecture (HSA) Foundation <http://www.hsafoundation.com/>`__
 .. [ELF] `Executable and Linkable Format (ELF) <http://www.sco.com/developers/gabi/>`__
 .. [DWARF] `DWARF Debugging Information Format <http://dwarfstd.org/>`__
 .. [YAML] `YAML Ain’t Markup Language (YAML™) Version 1.2 <http://www.yaml.org/spec/1.2/spec.html>`__
 .. [OpenCL] `The OpenCL Specification Version 2.0 <http://www.khronos.org/registry/cl/specs/opencl-2.0.pdf>`__
 .. [HRF] `Heterogeneous-race-free Memory Models <http://benedictgaster.org/wp-content/uploads/2014/01/asplos269-FINAL.pdf>`__
 .. [AMD-AMDGPU-Compute-Application-Binary-Interface] `AMDGPU Compute Application Binary Interface <https://github.com/RadeonOpenCompute/ROCm-ComputeABI-Doc/blob/master/AMDGPU-ABI.md>`__