drm/nve0/fifo: recover from mmu faults on bar1/bar3

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

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

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