drm/nvc0-/gr: factor out yet more unknown magic into versioned functions

NVC1/NVD9 are the only chipsets that should have anything different
happen on them after this.  We previously weren't doing these
register modifications, and NVIDIA do.

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

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvc0.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvc1.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvc3.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvc8.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvd7.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvd9.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnve4.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/ctxnvf0.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/graph/nvc0.h
Simple merge