mesa: validate sampler type across the whole program

mesa: validate sampler type across the whole program

Currently we were only making sure types were the same within a
single stage. This looks to have regressed with 953a0af8e3f73.

Fixes: 953a0af8e3f73 ("mesa: validate sampler uniforms during gluniform calls")
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
https://bugs.freedesktop.org/show_bug.cgi?id=97524