[gpu] Remove HasEquivalentBufferFormat and its checks

The CHECKs and some of the conditionals are mostly remnants of
BufferFormat conversions and can be removed.

Note: The only place left is OzoneImageBackingFactory
which I'll handle in a follow-up.

Bug: 356649879
Change-Id: Ie30eb98031259f4277779918a761474a59d05f80
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7540452
Reviewed-by: Joe Mason <joenotcharles@google.com>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: Saifuddin Hitawala <hitawala@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1580062}
NOKEYCHECK=True
GitOrigin-RevId: c75850df1926c4d380bf169dc4cc402b26ace566