[NFC][AMDGPU] DWARF Extensions For Heterogeneous Debugging clarifications

[t-tye]

Summary

Clarify that the base type endianity is used when creating implicit
location storage.

Remove duplicate definition of the generic type.

llvm/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.rst

 not match.
 
 .. _amdgpu-dwarf-expression-value:
 
 DWARF Expression Value
 ++++++++++++++++++++++
 
 A value has a type and a literal value. It can represent a literal value of any
-supported base type of the target architecture. The base type specifies the size
-and encoding of the literal value.
+supported base type of the target architecture. The base type specifies the
+size, encoding, and endianity of the literal value.
 
 .. note::
 
   It may be desirable to add an implicit pointer base type encoding. It would be
   used for the type of the value that is produced when the ``DW_OP_deref*``
   operation retrieves the full contents of an implicit pointer location storage
   created by the ``DW_OP_implicit_pointer`` or
   ``DW_OP_LLVM_aspace_implicit_pointer`` operations. The literal value would

 
 Value Operations
 ################
 
 This section describes the operations that push values on the stack.
 
 Each value stack entry has a type and a literal value and can represent a
 literal value of any supported base type of the target architecture. The base
-type specifies the size and encoding of the literal value.
+type specifies the size, encoding, and endianity of the literal value.
 
-Instead of a base type, value stack entries can have a distinguished generic
-type, which is an integral type that has the size of an address in the target
-architecture default address space and unspecified signedness.
-
-*The generic type is the same as the unspecified type used for stack operations
-defined in DWARF Version 4 and before.*
-
-An integral type is a base type that has an encoding of ``DW_ATE_signed``,
-``DW_ATE_signed_char``, ``DW_ATE_unsigned``, ``DW_ATE_unsigned_char``,
-``DW_ATE_boolean``, or any target architecture defined integral encoding in the
-inclusive range ``DW_ATE_lo_user`` to ``DW_ATE_hi_user``.
-
-.. note::
-
-  Unclear if ``DW_ATE_address`` is an integral type. GDB does not seem to
-  consider it as integral.
+The base type of value stack entries can be the distinguished generic type.
 
 .. _amdgpu-dwarf-literal-operations:
 
 Literal Operations
 ^^^^^^^^^^^^^^^^^^
 
 The following operations all push a literal value onto the DWARF stack.
 
1.  ``DW_OP_implicit_value``
 
     It pushes location description L with one implicit location description SL
     on the stack. SL specifies LS with a bit offset of 0.
 
 2.  ``DW_OP_stack_value``
 
     ``DW_OP_stack_value`` pops one stack entry that must be a value V.
 
-    An implicit location storage LS is created with the literal value V and a
-    size equal to V's base type size.
+    An implicit location storage LS is created with the literal value V using
+    the size, encoding, and enianity specified by V's base type.
 
     It pushes a location description L with one implicit location description SL
     on the stack. SL specifies LS with a bit offset of 0.
 
     *The* ``DW_OP_stack_value`` *operation specifies that the object does not
     exist in memory, but its value is nonetheless known. In this form, the
     location description specifies the actual value of the object, rather than
     specifying the memory or register storage that holds the value.*