ifb: fix a lockdep splat

After recent ifb changes, we must use lockless __skb_dequeue() since
lock is not anymore initialized.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Cc: Changli Gao <xiaosuo@gmail.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ifb.c

@@ -71,7 +71,7 @@ static void ri_tasklet(unsigned long dev)
 		}
 	}
 
-	while ((skb = skb_dequeue(&dp->tq)) != NULL) {
+	while ((skb = __skb_dequeue(&dp->tq)) != NULL) {
 		u32 from = G_TC_FROM(skb->tc_verd);
 
 		skb->tc_verd = 0;