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_

hipamd/src/hip_device_runtime.cpp

@@ -448,6 +448,9 @@ hipError_t hipDeviceGetAttribute(int* pi, hipDeviceAttribute_t attr, int device)
     case hipDeviceAttributeNumberOfXccs:
       *pi = static_cast<int>(g_devices[device]->devices()[0]->info().numberOfXccs_);
        break;
+    case hipDeviceAttributeMaxAvailableVgprsPerThread:
+      *pi = static_cast<int>(g_devices[device]->devices()[0]->info().availableVGPRs_);
+       break;
     default:
       HIP_RETURN(hipErrorInvalidValue);
   }