For some reason, flat shading on T604 does not work when using auto32 varyings
type.
This commit introduces a quirk for T60x, and some plumbing in pan_nir, allowing to
explicitely use appropriate types, rather than always using .u32 for flat shading.
Backport-to: 24.1
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10632
Signed-off-by: Alexandre Marquet <tb@a-marquet.fr>
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Acked-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28146>