drm/nouveau/device: provide a way for devinit to mark engines as disabled

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

diff --cc drivers/gpu/drm/nouveau/core/core/engine.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/include/core/device.h
Simple merge