Round up DMSAA attachments to pow2 if supported.

Change-Id: I03f5ea649209b9894753c981872edbd7d718288c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/408643
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
7 files changed