[graphite] Fix graphite iOS build.

Bug: skia:12466
Change-Id: Id0419836ca96d99836879d509ca2cd1c9244d76f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/461598
Commit-Queue: Greg Daniel <egdaniel@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Auto-Submit: Greg Daniel <egdaniel@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
1 file changed