Revert "net: bonding: fix error return code of bond_neigh_init()"

This reverts commit 2055a99d.

This change rejects legitimate configurations.

A slave doesn't need to exist nor implement ndo_slave_setup.
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -3978,15 +3978,11 @@ static int bond_neigh_init(struct neighbour *n)
 
 	rcu_read_lock();
 	slave = bond_first_slave_rcu(bond);
-	if (!slave) {
-		ret = -EINVAL;
+	if (!slave)
 		goto out;
-	}
 	slave_ops = slave->dev->netdev_ops;
-	if (!slave_ops->ndo_neigh_setup) {
-		ret = -EINVAL;
+	if (!slave_ops->ndo_neigh_setup)
 		goto out;
-	}
 
 	/* TODO: find another way [1] to implement this.
 	 * Passing a zeroed structure is fragile,