Revert "[graphite] Add Caps::channelMask()"

This reverts commit 8bb23e3b8943a010de83ac6cb27a1aa45253d86f.

Reason for revert: Link issues with Google3

Original change's description:
> [graphite] Add Caps::channelMask()
>
> Bug: b/238756380
> Change-Id: I855a424a1f10a14f521920aabedcaa24404a81ae
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/650956
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>

Bug: b/238756380
Change-Id: I5599ca3427c7c0c2a4012131269894d153c33875
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/651757
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
10 files changed