Enable HDP flush for all gfx9+ clients.

ucode versions are per asic so not valid for feature enablement outside
of bringup/dev.  Feature is older than the latest ioctl change that
the thunk depends on so use of this patch with kernel packages that
don't contain the feature is not possible in a supported environment.

Change-Id: I36b14176a7d642017ef1518aeade454b0f3dc749

runtime/hsa-runtime/core/runtime/amd_blit_sdma.cpp

@@ -141,8 +141,8 @@ hsa_status_t BlitSdma<RingIndexTy, HwIndexMonotonic, SizeToCountOffset>::Initial
     platform_atomic_support_ = link.info.atomic_support_64bit;
   }
 
-  // Determine if sDMA microcode supports HDP flush command
-  if (agent_->GetSdmaMicrocodeVersion() >= SDMA_PKT_HDP_FLUSH::kMinVersion_) {
+  // HDP flush supported on gfx900 and forward.
+  if (agent_->isa()->GetMajorVersion() > 8) {
     hdp_flush_support_ = true;
   }