Pre-nv50 YUV overlays have stringent requirements for working with the
internal machinery. Instead of rejecting these at update_plane time, we
should instead prevent the framebuffers from being created in the first
place.
Signed-off-by: NIlia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>