glsl: Delete unused gl_uniform_driver_format enum values.

glsl: Delete unused gl_uniform_driver_format enum values.

A while back, Matt made the uniform upload functions simply upload
ctx->Const.UniformBooleanTrue for boolean values instead of 0/1, which
removed the need to convert it later.  We also set UniformBooleanTrue to
1.0f for drivers which want to treat booleans as 0.0/1.0f.

Nothing ever sets these, so they are dead.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>