SWDEV-293519 - [PAL] Limit mgpu SVM logic only to mgpu cases

Below logic allocates the host buffer whenever a subbuffer is created
from a SVM allocation. This is only needed for multi-device contexts.

HIP does not support multi-device contexts, hence this logic just ends
up performing unnecessary system allocations.

Change-Id: I8eae635f7c5289c52ef73434218c1658b788a456


[ROCm/clr commit: ffbf368f4c]

projects/clr/rocclr/device/pal/paldevice.cpp

@@ -1396,7 +1396,8 @@ pal::Memory* Device::createBuffer(amd::Memory& owner, bool directAccess) const {
       return nullptr;
     }
 
-    if (nullptr != owner.parent()->getSvmPtr()) {
+    if ((nullptr != owner.parent()->getSvmPtr()) &&
+        (owner.parent()->getContext().devices().size() > 1)) {
       amd::Memory* amdParent = owner.parent();
       {
         // Lock memory object, so only one commitment will occur