drm/nouveau: Advertise correct modifiers on GB20x

drm/nouveau: Advertise correct modifiers on GB20x

8 and 16 bit formats use a different layout on
GB20x than they did on prior chips. Add the
corresponding DRM format modifiers to the list of
modifiers supported by the display engine on such
chips, and filter the supported modifiers for each
format based on its bytes per pixel in
nv50_plane_format_mod_supported().

Note this logic will need to be updated when GB10
support is added, since it is a GB20x chip that
uses the pre-GB20x sector layout for all formats.

Fixes: 6cc6e08d4542 ("drm/nouveau/kms: add support for GB20x")
Signed-off-by: James Jones <jajones@nvidia.com>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251030181153.1208-3-jajones@nvidia.com