panfrost: Lower user clip planes

Since we don't export the relevant CAP, the state tracker calls
nir_lower_clip_vs for us. However, for some reason we're still responsible for
calling nir_lower_clip_fs. Now that we have sane shader key infrastructure,
let's do so.

Fixes the floor rendering wrong in the title screen of Neverball.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16173>
4 files changed