drm/nouveau: greatly simplify mm, killing some bugs in the process

Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

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

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

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