drm/nouveau: require reservations for nouveau_fence_sync and nouveau_bo_fence

This will ensure we always hold the required lock when calling those functions.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>

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

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