atm: br2684: Fix oops due to skb->dev being NULL

This oops have been already fixed with commit

27141666b69f535a4d63d7bc6d9e84ee5032f82a

atm: [br2684] Fix oops due to skb->dev being NULL

It happens that if a packet arrives in a VC between the call to open it on
the hardware and the call to change the backend to br2684, br2684_regvcc
processes the packet and oopses dereferencing skb->dev because it is
NULL before the call to br2684_push().

but have been introduced again with commit

b6211ae7f2e56837c6a4849316396d1535606e90

atm: Use SKB queue and list helpers instead of doing it by-hand.

Signed-off-by: Daniel Schwierzeck <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/atm/br2684.c

···
 	spin_unlock_irqrestore(&rq->lock, flags);
 
 	skb_queue_walk_safe(&queue, skb, tmp) {
-		struct net_device *dev = skb->dev;
+		struct net_device *dev;
+
+		br2684_push(atmvcc, skb);
+		dev = skb->dev;
 
 		dev->stats.rx_bytes -= skb->len;
 		dev->stats.rx_packets--;
-
-		br2684_push(atmvcc, skb);
 	}
 
 	/* initialize netdev carrier state */