Make sure vISA honors forcing 128GRF number set by IGC.

Currently vISA honors forcing any GRF number except from 128, which is
the dedault on all platforms. This PR updates this behavior to honor 128
as well.

Author: jfuentes

visa/G4_Kernel.cpp

@@ -991,7 +991,7 @@ void G4_Kernel::setKernelParameters(unsigned newGRF) {
     grfMode.setModeByNumThreads(overrideNumThreads);
     overrideGRFNum = 0;
     autoGRFSelection = false;
-  } else if (overrideGRFNum != grfMode.getDefaultGRF()) {
+  } else if (overrideGRFNum > 0) {
     // Forcing a specific number of GRFs
     grfMode.setModeByNumGRFs(overrideGRFNum);
     autoGRFSelection = false;

visa/include/VISAOptionsDefs.h

@@ -293,7 +293,7 @@ DEF_VISA_OPTION(vISA_SpillMemOffset, ET_INT32, "-spilloffset",
 DEF_VISA_OPTION(vISA_ReservedGRFNum, ET_INT32, "-reservedGRFNum",
                 "USAGE: -reservedGRFNum <regNum>\n", 0)
 DEF_VISA_OPTION(vISA_TotalGRFNum, ET_INT32, "-TotalGRFNum",
-                "USAGE: -TotalGRFNum <regNum>\n", 128)
+                "USAGE: -TotalGRFNum <regNum>\n", 0)
 DEF_VISA_OPTION(vISA_RATrace, ET_BOOL, "-ratrace", UNUSED, false)
 DEF_VISA_OPTION(vISA_FastSpill, ET_BOOL, "-fasterRA", UNUSED, false)
 DEF_VISA_OPTION(vISA_AbortOnSpillThreshold, ET_INT32, "-abortOnSpill", UNUSED,