Fix a potential mem leak

If a offset of the pointer is passed to free it may release
the mem object but may not release from MemObjMap. Erase the map
by getting the parent pointer.
Change-Id: I06b92548de2d49b4029efe6b511329225007cc55


[ROCm/clr commit: 2b6fea4348]

projects/clr/rocclr/device/rocm/rocdevice.cpp

@@ -1903,8 +1903,8 @@ void Device::svmFree(void* ptr) const {
   amd::Memory* svmMem = nullptr;
   svmMem = amd::MemObjMap::FindMemObj(ptr);
   if (nullptr != svmMem) {
+    amd::MemObjMap::RemoveMemObj(svmMem->getSvmPtr());
     svmMem->release();
-    amd::MemObjMap::RemoveMemObj(ptr);
   }
 }