net: usb: log errors to dmesg/syslog

Errors in protocol should be logged when the driver aborts operations.
If the driver can carry on and "humor" the device, then emitting
the message as debug output level is fine.
Signed-off-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/usbnet.c

@@ -887,7 +887,7 @@ int usbnet_open (struct net_device *net)
 
 	// insist peer be connected
 	if (info->check_connect && (retval = info->check_connect (dev)) < 0) {
-		netif_dbg(dev, ifup, dev->net, "can't open; %d\n", retval);
+		netif_err(dev, ifup, dev->net, "can't open; %d\n", retval);
 		goto done;
 	}