[SCSI] fcoe: removes reserving memory for vlan_ethdr on tx path

This is not required as VLAN header is added by device
interface driver, this was causing bad FC_CRC in FCoE pkts when
using VLAN interface.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>