virtio_net: hook up the set-tso ethtool op

Seems like an oversight that we have set-tx-csum and set-sg hooked
up, but not set-tso.

Also leads to the strange situation that if you e.g. disable tx-csum,
then tso doesn't get disabled.
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

@@ -481,6 +481,7 @@ static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 static struct ethtool_ops virtnet_ethtool_ops = {
 	.set_tx_csum = virtnet_set_tx_csum,
 	.set_sg = ethtool_op_set_sg,
+	.set_tso = ethtool_op_set_tso,
 };
 
 static int virtnet_probe(struct virtio_device *vdev)