Independently of the type of tunnel, encapsulated packet
can be either v6 or v4, so we need to create 2 faces for each
version of the tunnel. Currently we are wrongly associating v4
tunnels with v4 packets and v6 tunnel with v6 packets.

Tunneled hicn packet MUST have locator set to the loopback
address, so ::1 for IPv6 and 127.0.0.1 for IPv4.