Apply setImageLayout() to all of a VkImage's subresources.

Apply setImageLayout() to all of a VkImage's subresources.

This also adds fLevelCount to GrVkImage::Resource, which allows
clients to wrap mipmapped textures.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1943933002
TBR=bsalomon@google.com

Review-Url: https://codereview.chromium.org/1943933002