We would try to create SRVs with zero mip levels, when we should
be asking for a single mip level. This would happen when the base
level is equal to the max level. See the dEQP test:

texture.mipmap.2d.max_level.linear_nearest

Change-Id: I3f231f159dbdecbf7c2e61b373bfc3545875f36e
Reviewed-on: https://chromium-review.googlesource.com/240762Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>