drm/amd/display: Ensure commit_streams returns the DC return code

[Description]
- Ensure dc_commit_streams returns the correct return code so any
  failures can be handled properly in DM layer
- If set timings fail and we have to remove MPO planes, do so
  unconditionally but make sure to mark for removal so we report
  the VSYNC and prevent timeout
- Failure to remove MPO plane results in set timings failure due
  to lack of resources

Reviewed-by: Aric Cyr <[email protected]>
Acked-by: Stylon Wang <[email protected]>
Signed-off-by: Alvin Lee <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Alvin Lee

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

@@ -1988,7 +1988,7 @@ enum dc_status dc_commit_streams(struct dc *dc,
 
 	DC_LOG_DC("%s Finished.\n", __func__);
 
-	return (res == DC_OK);
+	return res;
 }
 
 /* TODO: When the transition to the new commit sequence is done, remove this