iavf: Add framework to enable ethtool ntuple filters

Enable ethtool ntuple filter support on the VF driver using the virtchnl
interface to the PF driver and the Flow director functionality in the
hardware.

Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
Tested-by: Chen Bo <BoX.C.Chen@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>