net: convert remaining non-symbolic return values in dev_queue_xmit

Patch compiled and 32 simultaneous netperf testing ran fine.
Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1917,7 +1917,7 @@ gso:
 			HARD_TX_LOCK(dev, txq, cpu);
 
 			if (!netif_tx_queue_stopped(txq)) {
-				rc = 0;
+				rc = NET_XMIT_SUCCESS;
 				if (!dev_hard_start_xmit(skb, dev, txq)) {
 					HARD_TX_UNLOCK(dev, txq);
 					goto out;