Remove unused GrPixelConfig functions

Change-Id: I1847a96cb8253a8bd047c06d24cba92c8dc04667
Reviewed-on: https://skia-review.googlesource.com/140440
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed