meta: Only bind the sampler in one place

meta: Only bind the sampler in one place

All of the calls after the first _mesa_bind_sampler call are DSA style
calls that don't depend on the current binding.

I kept this change separate and last because it is one of the few in the
series that is not a candidate for the stable branch.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>