SkGainmapInfo: Fix typos in comments

Bug: skia:14031
Change-Id: Iaab47b3a33f653a89d99807d5aa54d10c1f93742
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/643578
Commit-Queue: Christopher Cameron <ccameron@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed