ixgbe: Implement FCoE Tx side offload features in base driver of 82599

This patch implements the FCoE Tx side offload features in ixgbe_main.c
to 82599 using the Tx offload infrastructure code added in the previous
patch. This is achieved by the calling the FCoE Sequence Offload (FSO)
function ixgbe_fso() on the transmit path of ixgbe.

This patch also includes an EEPROM check to make sure the NIC we're loading
on is an offload-enabled SKU.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>