bridge: fix error handling in br_add_if()

When device is added to bridge its refcnt is incremented (in new_nbp()), but if
error occurs during further br_add_if() operations this counter is not
decremented back. Fix it by adding dev_put() call in the error path.
Signed-off-by: Volodymyr G Lukiianyk <volodymyrgl@gmail.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_if.c

@@ -411,9 +411,12 @@ err2:
 	br_fdb_delete_by_port(br, p, 1);
 err1:
 	kobject_del(&p->kobj);
-	return err;
+	goto put_back;
 err0:
 	kobject_put(&p->kobj);
+
+put_back:
+	dev_put(dev);
 	return err;
 }