[graphite] Add remaining factories to MtlTexture.

Adds factory for SampledTextures and MSAA textures

Bug: skia:12466
Change-Id: Ia8aa7fa874e8256fe4dea8a16ceb459dbb02547d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/455618
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
2 files changed