If you allow an unsupported component count in the callback for loads,
nir_opt_load_store_vectorize will align num_components to the next supported
vector size, essentially overfetching.
This changes all callbacks to reject it. AMD will enable it in a later commit.
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29398>