SWDEV-508776 - support VGPRs validation (#274)

Clarify some VGPRs terms description.
Fix some wrong query logics of availableVGPRs_ and
availableRegistersPerCU_ in device info.
Add hipDeviceAttributeMaxAvailableVgprsPerThread
attribute query.
Remove hardcoding of following
 info_.vgprAllocGranularity_
 info_.vgprsPerSimd_

[ROCm/clr commit: 397f303d97]

projects/clr/rocclr/device/devkernel.cpp

@@ -619,7 +619,7 @@ Kernel::Kernel(const amd::Device& dev, const std::string& name, const Program& p
   workGroupInfo_.usedGPRs_ = 0;
   workGroupInfo_.availableSGPRs_ = 0;
   workGroupInfo_.usedSGPRs_ = 0;
-  workGroupInfo_.availableVGPRs_ = 0;
+  workGroupInfo_.availableVGPRs_ = dev.info().availableVGPRs_;
   workGroupInfo_.usedVGPRs_ = 0;
   workGroupInfo_.availableLDSSize_ = 0;
   workGroupInfo_.usedLDSSize_ = 0;