drm/nv108/fifo: initial support

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/device/nve0.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/core/engine/fifo/nv108.c
Simple merge

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