bonding: change error message to debug message in __bond_release_one()

In __bond_release_one(), when the interface is not a slave or not a slave of
"this" master, it log error message.

The message actually should be a debug message matching what bond_enslave()
does.
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Acked-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: Andy Gospodarek <gospo@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1648,7 +1648,7 @@ static int __bond_release_one(struct net_device *bond_dev,
 	/* slave is not a slave or master is not master of this slave */
 	if (!(slave_dev->flags & IFF_SLAVE) ||
 	    !netdev_has_upper_dev(slave_dev, bond_dev)) {
-		netdev_err(bond_dev, "cannot release %s\n",
+		netdev_dbg(bond_dev, "cannot release %s\n",
 			   slave_dev->name);
 		return -EINVAL;
 	}