ixgbe: Add hardware defines for Flow Director for 82599

Flow Director is a Rx filter mechanism designed to match Rx flows back to
the same CPU that the flow's Tx occurred from.  This patch adds the first
piece, the defines for the hardware registers, to enable this feature in
82599 hardware.

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>