[Pixman] [PATCH] lowlevel-blt-bench: use a8r8g8b8 for CA solid masks

[Ben Avison]

> When doing component alpha, use a mask format that has all the color
> channels instead of just a8.

In case you're waiting for me...

That first sentence doesn't qualify the fact that this is specific to
solid masks. Other than that, looks good to me. Not sure whether that
qualifies as a Reviewed-by or Acked-by, take your pick!

Ben