drm/nouveau/pm: fix a typo related to the move to the therm subdev

Reported-by: Vekin on IRC
Reported-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Martin Peres <martin.peres@labri.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_pm.c

@@ -52,7 +52,7 @@ nouveau_pm_perflvl_aux(struct drm_device *dev, struct nouveau_pm_level *perflvl,
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nouveau_pm *pm = nouveau_pm(dev);
-	struct nouveau_therm *therm = nouveau_therm(drm);
+	struct nouveau_therm *therm = nouveau_therm(drm->device);
 	int ret;
 
 	/*XXX: not on all boards, we should control based on temperature