sonic: Fix build after ndo_start_xmit() changes.

Noticed by Stephen Rothwell.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/sonic.c

@@ -223,7 +223,7 @@ static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev)
 	if (!laddr) {
 		printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name);
 		dev_kfree_skb(skb);
-		return NETDEV_TX_BUSY
+		return NETDEV_TX_BUSY;
 	}
 
 	sonic_tda_put(dev, entry, SONIC_TD_STATUS, 0);       /* clear status */