s390/qeth: switch on SG by default for IQD devices

Scatter-gather transmit brings a nice performance boost. Considering the
rather large MTU sizes at play, it's also totally the Right Thing To Do.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core_main.c

@@ -5706,6 +5706,8 @@ static struct net_device *qeth_alloc_netdev(struct qeth_card *card)
 		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 		dev->hw_features |= NETIF_F_SG;
 		dev->vlan_features |= NETIF_F_SG;
+		if (IS_IQD(card))
+			dev->features |= NETIF_F_SG;
 	}
 
 	return dev;