Remove more gcc warnings.

[abidh]

Summary

I saw following gcc warnings in 3 places and they seem to make sense.

"comparison of unsigned expression >= 0 is always true [-Wtype-limits]"

To fix the warnings, I have removed the offending checks. OK?

[clayborg]

Please don't check this in. If dwarf_r0 changes from 0 to another value, then this code will fail. We will need to live with these warnings.

source/Plugins/Instruction/ARM/EmulationStateARM.cpp

EmulationStateARM::LoadPseudoRegistersFromFrame (StackFrame &frame)
     }
     
     return success;
 }
     
 bool
 EmulationStateARM::StorePseudoRegisterValue (uint32_t reg_num, uint64_t value)
 {
-    if ((dwarf_r0 <= reg_num) && (reg_num <= dwarf_cpsr))
+    if (reg_num <= dwarf_cpsr)
         m_gpr[reg_num  - dwarf_r0] = (uint32_t) value;
     else if ((dwarf_s0 <= reg_num) && (reg_num <= dwarf_s31))
     {
         uint32_t idx = reg_num - dwarf_s0;
         m_vfp_regs.sd_regs[idx / 2].s_reg[idx % 2] = (uint32_t) value;
     }
     else if ((dwarf_d0 <= reg_num) && (reg_num <= dwarf_d31))
     {

 }
     
 uint64_t
 EmulationStateARM::ReadPseudoRegisterValue (uint32_t reg_num, bool &success)
 {
     uint64_t value = 0;
     success = true;
     
-    if ((dwarf_r0 <= reg_num) && (reg_num <= dwarf_cpsr))
+    if (reg_num <= dwarf_cpsr)
         value = m_gpr[reg_num  - dwarf_r0];
     else if ((dwarf_s0 <= reg_num) && (reg_num <= dwarf_s31))
     {
         uint32_t idx = reg_num - dwarf_s0;
         value = m_vfp_regs.sd_regs[idx / 2].s_reg[idx % 2];
     }
     else if ((dwarf_d0 <= reg_num) && (reg_num <= dwarf_d31))
     {

source/Utility/ARM64_DWARF_Registers.cpp

 }
 
 bool
 arm64_dwarf::GetRegisterInfo (unsigned reg_num, RegisterInfo &reg_info)
 {
     ::memset (&reg_info, 0, sizeof(RegisterInfo));
     ::memset (reg_info.kinds, LLDB_INVALID_REGNUM, sizeof(reg_info.kinds));
     
-    if (reg_num >= x0 && reg_num <= pc)
+    if (reg_num <= pc)
     {
         reg_info.byte_size = 8;
         reg_info.format = eFormatHex;
         reg_info.encoding = eEncodingUint;
     }
     else if (reg_num >= v0 && reg_num <= v31)
     {
         reg_info.byte_size = 16;