Update GrRTC to use GrFillRectOp::MakeGeneric

Change-Id: I4b137c545e726a49c7c5a64febdb83388f335e08
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/215082
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
1 file changed