[SCSI] net, fcoe: add ETH_P_FCOE for Fibre Channel over Ethernet (FCoE)

This adds eth type ETH_P_FCOE for Fibre Channel over Ethernet (FCoE),
consequently, the ETH_P_FCOE from fc_fcoe.h and fcoe skb->protocol
is not set as ETH_P_FCOE.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>