Implement flat scratch support for dGPU

hsaKmtAllocMemory only allocates aligned address space and sets up
the scratch_physical aperture to match the allocated address space.

Actual allocation of backing memory happens in hsaKmtMapMemoryToGPU.

Change-Id: Ie709815ab9bedb3d682e096b4005fdfb5e94d3a7

src/memory.c

@@ -155,7 +155,7 @@ hsaKmtAllocMemory(
 		return HSAKMT_STATUS_SUCCESS;
 	}
 
-	if (!MemFlags.ui32.HostAccess && MemFlags.ui32.NonPaged) {
+	if (!MemFlags.ui32.HostAccess && MemFlags.ui32.NonPaged && !MemFlags.ui32.Scratch) {
 		*MemoryAddress = fmm_allocate_device(gpu_id, SizeInBytes);
 
 		if (*MemoryAddress == NULL)
@@ -163,7 +163,7 @@ hsaKmtAllocMemory(
 
 		return HSAKMT_STATUS_SUCCESS;
 	}
-	if (MemFlags.ui32.HostAccess && MemFlags.ui32.Scratch ) { 
+	if (MemFlags.ui32.Scratch ) {
 		*MemoryAddress = fmm_allocate_scratch(gpu_id, SizeInBytes);
 
 		if (*MemoryAddress == NULL)