drm/nouveau: remove remnants of nouveau_pgraph_engine

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

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

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

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

diff --cc drivers/gpu/drm/nouveau/nouveau_drv.h
Simple merge

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

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

diff --cc drivers/gpu/drm/nouveau/nv20_graph.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nv50_graph.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nvc0_graph.c
Simple merge