drm/nouveau: use drm_send_vblank_event() helper

	}

	s = list_first_entry(&fctx->flip, struct nouveau_page_flip_state, head);

	if (s->event) {

		struct drm_pending_vblank_event *e = s->event;

		struct timeval now;

		do_gettimeofday(&now);

		e->event.sequence = 0;

		e->event.tv_sec = now.tv_sec;

		e->event.tv_usec = now.tv_usec;

		list_add_tail(&e->base.link, &e->base.file_priv->event_list);

		wake_up_interruptible(&e->base.file_priv->event_wait);

	}

	if (s->event)

		drm_send_vblank_event(dev, -1, s->event);

	list_del(&s->head);

	if (ps)