mesa: fix per-level max texture size error checking

mesa: fix per-level max texture size error checking

This is a long-standing omission in Mesa's texture image size checking.
We need to take the mipmap level into consideration when checking if the
width, height and depth are too large.

Fixes the new piglit max-texture-size-level test.
Thanks to Stéphane Marchesin for finding this problem.

Note: This is a candidate for the stable branches.

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>