Enable GPU memory in HMM by default

Change-Id: Ifec4733dc7a932163d921ebe1ae9fbd594ea1ef2

rocclr/device/rocm/rocsettings.cpp

@@ -87,7 +87,7 @@ Settings::Settings() {
   lcWavefrontSize64_ = true;
   imageBufferWar_ = false;
 
-  hmmFlags_ = (!flagIsDefault(ROC_HMM_FLAGS)) ? ROC_HMM_FLAGS : Hmm::EnableSystemMemory;
+  hmmFlags_ = (!flagIsDefault(ROC_HMM_FLAGS)) ? ROC_HMM_FLAGS : 0;
 
   rocr_backend_ = true;
   barrier_sync_ = (!flagIsDefault(ROC_BARRIER_SYNC)) ? ROC_BARRIER_SYNC : true;