drm/nouveau/kms/gk104-gp1xx: Fix > 64x64 cursors

While we do handle the additional cursor sizes introduced in NVE4, it looks
like we accidentally broke this when converting over to use Nvidia's
display headers. Since we now use NVVAL in dispnv50/head907d.c in order to
format the value for the cursor layout and NVD9 only had one byte reserved
vs. the 2 bytes reserved in later generations, we end up accidentally
stripping the second bit in the cursor layout format parameter - causing us
to set the wrong cursor size.

This fixes that by adding our own curs_set hook for 917d which uses the
NV917D headers.

Cc: Martin Peres <martin.peres@free.fr>
Cc: Jeremy Cline <jcline@redhat.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: <stable@vger.kernel.org> # v5.9+
Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: ed0b86a9

 ("drm/nouveau/kms/nv50-: use NVIDIA's headers for core head_curs_set()")
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>