anv/meta2d: Don't declare an array sampler in the fragment shader

anv/meta2d: Don't declare an array sampler in the fragment shader

With the new blit framework we aren't using array textures and, from
talking with Nanley, we don't think it's going to be useful in the future
either.  Just get rid of it for now.

Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>