net: ethernet: cadence: fix socket buffer corruption problem

Socket buffer is not re-created when headroom is 2 and tailroom is 1.
Signed-off-by: NTristram Ha <Tristram.Ha@microchip.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb_main.c

@@ -1684,7 +1684,7 @@ static int macb_pad_and_fcs(struct sk_buff **skb, struct net_device *ndev)
 			padlen = 0;
 		/* No room for FCS, need to reallocate skb. */
 		else
-			padlen = ETH_FCS_LEN - tailroom;
+			padlen = ETH_FCS_LEN;
 	} else {
 		/* Add room for FCS. */
 		padlen += ETH_FCS_LEN;