Indicate texel buffer support in Vulkan

Bug: skia:
Change-Id: I116dd2b15320e3a61afba82b003b13a14ce6122f
Reviewed-on: https://skia-review.googlesource.com/21402
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2 files changed