drm/amd/display: Let updates with no scaling changes be fast

[Why]
DC was assuming that any surface_update->scaling_info
meant the update was at least medium.  However, if nothing
has changed there is no scaling to program, so there is
no problem with the update being fast

[How]
If every update flag is not set, the update is fast
Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Acked-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -1240,7 +1240,7 @@ static enum surface_update_type get_plane_info_update_type(const struct dc_surfa
 			|| update_flags->bits.output_tf_change)
 		return UPDATE_TYPE_FULL;
 
-	return UPDATE_TYPE_MED;
+	return update_flags->raw ? UPDATE_TYPE_MED : UPDATE_TYPE_FAST;
 }
 
 static enum surface_update_type get_scaling_info_update_type(