nir/lower_amul: Use num_ubos/ssbos instead of recomputing it.

Now that num_ubos is correctly maintained, we can just trust it.  Fixes an
assertion failure in freedreno I triggered on
dEQP-GLES31.functional.ubo.random.all_per_block_buffers.1 for reasons I
don't really understand.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6179>
1 file changed