Remove unused VkFuchsiaImageFormatFUCHSIA

Change-Id: Ie73e92ee4d3213d38ff614c8cec40d92f152bcc4
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/mesa/+/445374
Reviewed-by: John Bauman <jbauman@google.com>
5 files changed