iavf: Support IPv4 Flow Director filters

Support the addition and deletion of IPv4 filters.

Supported fields are: src-ip, dst-ip, src-port, dst-port and l4proto
Supported flow-types are: tcp4, udp4, sctp4, ip4, ah4, esp4

Example usage:
ethtool -N ens787f0v0 flow-type tcp4 src-ip 192.168.0.20 \
  dst-ip 192.168.0.21 tos 4 src-port 22 dst-port 23 action 8

L2TPv3 over IP with 'Session ID' 17:
ethtool -N ens787f0v0 flow-type ip4 l4proto 115 l4data 17 action 3

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>