bonding: trivial: remove forgotten bond_next_vlan()

It's a forgotten function declaration, which was removed some time ago
already.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bonding.h

@@ -398,7 +398,6 @@ static inline bool slave_can_tx(struct slave *slave)
 struct bond_net;
 
 int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond, struct slave *slave);
-struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr);
 int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
 void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int slave_id);
 int bond_create(struct net *net, const char *name);