taskqueue_cancel_timeout
if (taskqueue_cancel_timeout(ic->ic_tq, scan_task, NULL) == 0)
taskqueue_cancel_timeout(ic->ic_tq, &ss_priv->ss_scan_curchan,
int taskqueue_cancel_timeout(struct taskqueue *queue,
taskqueue_cancel_timeout(_taskqueue_thread, &ar->ar_task, NULL);