drm: when queuing an event with NEXTONMISS, return queued sequence to userspace

If we queue a vblank event but miss it, we should return the actual
sequence number we queued to userspace, so its event handling function
will know which event to look for.
Acked-by: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_irq.c

@@ -558,6 +558,7 @@ static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
 	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
 	    (seq - vblwait->request.sequence) <= (1 << 23)) {
 		vblwait->request.sequence = seq + 1;
+		vblwait->reply.sequence = vblwait->request.sequence;
 	}
 
 	DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",