bonding: Fix reference count leak in bond_sysfs_slave_add.

kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object. Previous
commit "b8eb718348b8" fixed a similar problem.

Fixes: 07699f9 ("bonding: add sysfs /slave dir for bond slave devices.")
Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_sysfs_slave.c

@@ -149,8 +149,10 @@ int bond_sysfs_slave_add(struct slave *slave)
 
 	err = kobject_init_and_add(&slave->kobj, &slave_ktype,
 				   &(slave->dev->dev.kobj), "bonding_slave");
-	if (err)
+	if (err) {
+		kobject_put(&slave->kobj);
 		return err;
+	}
 
 	for (a = slave_attrs; *a; ++a) {
 		err = sysfs_create_file(&slave->kobj, &((*a)->attr));