SkImage_GpuYUVA: Also sanity check height

We were sanity checking the width twice; we switch to checking
the width and height.

Change-Id: I0841eaeeb9c42af2e309e0dafa5ec0b1843a71a8
Reviewed-on: https://skia-review.googlesource.com/c/191061
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed