if_ether: add forces ife lfb type

This patch adds the forces IFE lfb type according to IEEE registered
ethertypes. See http://standards-oui.ieee.org/ethertype/eth.txt for more
information. Since there exists the IFE subsystem it can be used there.

This patch also use the correct word "ForCES" instead of "FoRCES" which
is a spelling error inside the IEEE ethertype specification.

Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>