mesa: Disallow SNORM formats for renderbuffers in OpenGL ES

v2: Move {RED,RG,RGB,RGBA}_SNORM changes from the previous commit to
this commit.  Based on suggestions from Ken.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Marek Olšák <maraeo@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
1 file changed