panfrost: Only key points to point coord origin

panfrost: Only key points to point coord origin

Apparently, the point coord origin within a batch can change with Gallium
(seemingly even with GLES? where that's impossible at an API level?) but that
doesn't matter if we're not drawing points. This might have to do with internal
Gallium CSOs (e.g. u_blitter). Issue noticed in SuperTuxKart, which was getting
state change flushes. Performance on one level on a Valhall GPU improved from
26fps to 29fps.

Fixes: 3641dfe4367 ("panfrost: Flip point coords in hardware")
Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17430>