ixgbe: Add fdir support for SCTP on X550

X550 has HW support for SCTP flow director filters SCTP mask. This
patch adds it like we do for UDP and TCP.

Signed-off-by: Donald C Skidmore <donald.c.skidmore@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>