drm/nouveau/fifo: add GK20A support

GK20A's FIFO is compatible with NVE0, but only features 128 channels and
1 runlist.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --cc drivers/gpu/drm/nouveau/Makefile
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/fifo/gk20a.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/fifo/nve0.h
Simple merge

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