Add support for 'flow-type ether' Flow Director rules via ethtool.

Create packet segment info for filter configuration based on ethtool
command parameters. Reuse infrastructure already created for
ipv4 and ipv6 flows to convert packet segment into
extraction sequence, which is later used to program the filter
inside Flow Director block of the Rx pipeline.

Rules not containing masks are processed by the Flow Director,
and support the following set of input parameters in all combinations:
src, dst, proto, vlan-etype, vlan, action.

It is possible to specify address mask in ethtool parameters but only
00:00:00:00:00 and FF:FF:FF:FF:FF are valid.
The same applies to proto, vlan-etype and vlan masks:
only 0x0000 and 0xffff masks are valid.

Testing:
  (DUT) iperf3 -s
  (DUT) ethtool -U ens785f0np0 flow-type ether dst <ens785f0np0 mac> \
        action 10
  (DUT) watch 'ethtool -S ens785f0np0 | grep rx_queue'
  (LP)  iperf3 -c ${DUT_IP}

  Counters increase only for:
    'rx_queue_10_packets'
    'rx_queue_10_bytes'
Signed-off-by: Jakub Buchocki <jakubx.buchocki@intel.com>
Co-developed-by: Mateusz Pacuszka <mateuszx.pacuszka@intel.com>
Signed-off-by: Mateusz Pacuszka <mateuszx.pacuszka@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Lukasz Plachno <lukasz.plachno@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>