Re-Enable IPC DMA Bufs by default

Let ROCr use the new IPC-DMA bufs path.

projects/rocr-runtime/runtime/hsa-runtime/core/util/flag.h

@@ -242,7 +242,8 @@ class Flag {
     enable_mwaitx_ = (var == "1") ? true : false;
 
     var = os::GetEnvVar("HSA_ENABLE_IPC_MODE_LEGACY");
-    enable_ipc_mode_legacy_ = (var == "0") ? false : true; // Legacy mode by default
+    enable_ipc_mode_legacy_ = (var == "1") ? true : false;
+
     if (os::IsEnvVarSet("HSA_PCS_MAX_DEVICE_BUFFER_SIZE")) {
       var = os::GetEnvVar("HSA_PCS_MAX_DEVICE_BUFFER_SIZE");
       char* end;