ixgbe: Add infrastructure code for FCoE large send offload to 82599

This adds infrastructure code for FCoE Tx side offload feature to
82599, including Fiber Channel CRC calculation, auto insertion of
the start of frame (SOF) and end of frame (EOF) of FCoE packets,
and large send by FCoE Sequence Offload (FSO).

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>