flow: add vnet/flow formal API
This patch adds the API for vnet/flow infra.
Currently this API supports the below flow types:
VNET_FLOW_TYPE_IP4_N_TUPLE
VNET_FLOW_TYPE_IP6_N_TUPLE
VNET_FLOW_TYPE_IP4_N_TUPLE_TAGGED
VNET_FLOW_TYPE_IP6_N_TUPLE_TAGGED
VNET_FLOW_TYPE_IP4_L2TPV3OIP
VNET_FLOW_TYPE_IP4_IPSEC_ESP
VNET_FLOW_TYPE_IP4_IPSEC_AH
VNET_FLOW_TYPE_IP4_GTPU
All the above flows are tested with Intel E810/X710 NIC
Type: feature
Signed-off-by: Chenmin Sun <chenmin.sun@intel.com>
Change-Id: Icb8ae20cab9bdad6b120dddc3bd4fb1d85634f3f