Remove unused RP stage pointer

Change-Id: I73922717d4ebd8c759f7fe5c7c8e8da4567a0aa9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/430039
Commit-Queue: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
1 file changed