ixgbe: Add FCoE feature code to 82599

This adds the FCoE feature code ixgbe_fcoe.c to 82599. For a start, this patch
only adds ixgbe_configure_fcoe() to configure related register for FCoE to 82599.
In patches that follow, I will be adding more functions to ixgbe_fcoe.c to add
support of FCoE offload features to 82599.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Acked-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>