ifb: fix packets checksum

Fixup the checksum for CHECKSUM_COMPLETE when pulling skbs on RX path.
Otherwise we get splats when tc mirred is used to redirect packets to ifb.

Before fix:

nic: hw csum failure
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ifb.c

@@ -102,7 +102,7 @@ static void ifb_ri_tasklet(unsigned long _txp)
 		if (!skb->tc_from_ingress) {
 			dev_queue_xmit(skb);
 		} else {
-			skb_pull(skb, skb->mac_len);
+			skb_pull_rcsum(skb, skb->mac_len);
 			netif_receive_skb(skb);
 		}
 	}