ANGLE always enables the Mipmap. The fix does redefining
the image with mipmaps and replace the origin one only
when it is necessary.

Bug: angleproject:3737
Change-Id: Ia33a16fd7feae303fb114988059c4eec58c4232d
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1750627
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Ian Elliott <ianelliott@google.com>