Fix noncoherent advanced blend eq NV workaround

It should only be applied when the coherent extension is not available.

Change-Id: Ic6a8b344b78634bbc996e2feb911bd82e06dec4a
Reviewed-on: https://skia-review.googlesource.com/99220
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed