virtio_net: remove overzealous printk

The 'disable_cb' is really just a hint and as such, it's possible for more
work to get queued up while callbacks are disabled.  Under stress with an
SMP guest, this printk triggers very frequently.  There is no race here, this
is how things are designed to work so let's just remove the printk.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/net/virtio_net.c

@@ -284,7 +284,6 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 		/* Activate callback for using skbs: if this returns false it
 		 * means some were used in the meantime. */
 		if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-			printk("Unlikely: restart svq race\n");
 			vi->svq->vq_ops->disable_cb(vi->svq);
 			netif_start_queue(dev);
 			goto again;