drm/nve0: magic up some support for GF117

Seen in the wild, don't have the hardware but this hacks things up to
treat it the same as GF119 for now.

Should be relatively safe, I'd be very surprised if anything major
changed outside of PGRAPH.  PGRAPH (3D etc) is disabled by default
however until it's confirmed working.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>