drm/nouveau/pmu: make sure the reset hook exists before running it

Some PMU implementations (in particular the ones managed by secure
boot) may not have a reset() hook. Make sure we don't crash in that
case.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
1 file changed