bonding: trivial: remove unused parameter from alb_swap_mac_addr()

After b924551b

 ("bonding: fix enslaving in alb mode when link down") we
don't need the bond parameter in alb_swap_mac_addr(), so remove it.

Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>