net: fix IFF_NO_QUEUE for drivers using alloc_netdev

Printing a warning in alloc_netdev_mqs() if tx_queue_len is zero and
IFF_NO_QUEUE not set is not appropriate since drivers may use one of the
alloc_netdev* macros instead of alloc_etherdev*, thereby not
intentionally leaving tx_queue_len uninitialized. Instead check here if
tx_queue_len is zero and set IFF_NO_QUEUE, so the value of tx_queue_len
can be ignored in net/sched_generic.c.

Fixes: 906470c1 ("net: warn if drivers set tx_queue_len = 0")
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -7010,7 +7010,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	setup(dev);
 
 	if (!dev->tx_queue_len)
-		printk(KERN_WARNING "%s uses DEPRECATED zero tx_queue_len - convert driver to use IFF_NO_QUEUE instead.\n", name);
+		dev->priv_flags |= IFF_NO_QUEUE;
 
 	dev->num_tx_queues = txqs;
 	dev->real_num_tx_queues = txqs;