Add API for available GPU memory

Add support for AMD Agent to return amount of memory available

Change-Id: I5c32e2cebbaa2993b044250aefe434e4cc02d8c2
Signed-off-by: David Yat Sin <david.yatsin@amd.com>

runtime/hsa-runtime/core/inc/amd_memory_region.h

@@ -138,6 +138,8 @@ class MemoryRegion : public core::MemoryRegion {
 
   void Trim() const;
 
+  HSAuint64 GetCacheSize() const { return fragment_allocator_.cache_size(); }
+
   __forceinline bool IsLocalMemory() const {
     return ((mem_props_.HeapType == HSA_HEAPTYPE_FRAME_BUFFER_PRIVATE) ||
             (mem_props_.HeapType == HSA_HEAPTYPE_FRAME_BUFFER_PUBLIC));