drm/nouveau: dont switch vt on suspend

Restore the nv50 cursor bo on resume, and load the lut in
nv50_display_display_init so it gets set on resume too.

Tested on a fermi and a curie.

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