Fix handling of red support for GalliumLLVM renderer

Change-Id: Ia4a71ca336a43dd2717a6aa4b5e254cd46406228
Reviewed-on: https://skia-review.googlesource.com/97061
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
1 file changed