drm/nv31/mpeg: store chan singleton in engine, use it for dispatch

This makes nv31+ able to actually perform the nv_call, since previously
the inst was not available.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
2 files changed