on gk208+ we can simply mov 32bits, so we should have a single mov there

v2: use or operator instead of add
Signed-off-by: NKarol Herbst <nouveau@karolherbst.de>
Reviewed-by: NMartin Peres <martin.peres@free.fr>
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>