mesa/drawtex: Cut out the TGSI semantic translation.

Now that we don't have to generate TGSI, we can drop an indirection.
Fixing up the types here prompted a little fixup of
st_nir_make_passthrough_shader()'s types.

Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23114>
5 files changed