bonding sometimes uses Ethernet constants (such as MTU and address length) which
are not good when it enslaves non Ethernet devices (such as InfiniBand).

Signed-off-by: Moni Shoua <monis at voltaire.com>
Acked-by: NJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>