RDMA/cm: Abort loop in case of CM dequeue

In case CM work list is empty, the work pointer will be NULL,
so instead of kernel crash it is better to abort processing
of works.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/cm.c

@@ -1707,7 +1707,9 @@ static void cm_process_work(struct cm_id_private *cm_id_priv,
 		spin_lock_irq(&cm_id_priv->lock);
 		work = cm_dequeue_work(cm_id_priv);
 		spin_unlock_irq(&cm_id_priv->lock);
-		BUG_ON(!work);
+		if (!work)
+			return;
+
 		ret = cm_id_priv->id.cm_handler(&cm_id_priv->id,
 						&work->cm_event);
 		cm_free_work(work);