drm/amdgpu: add AVFS control to PP_FEATURE_MASK

Add a ppfeaturemask flag to disable AVFS control.
Reviewed-by: NRex Zhu <Rex.Zhu@amd.com>
Reviewed-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/include/amd_shared.h

@@ -129,6 +129,7 @@ enum PP_FEATURE_MASK {
 	PP_GFXOFF_MASK = 0x8000,
 	PP_ACG_MASK = 0x10000,
 	PP_STUTTER_MODE = 0x20000,
+	PP_AVFS_MASK = 0x40000,
 };
 
 /**