If status is 0, both ip_hdr and proto_hdr will own a pointer to the
relevant IP and Protocol headers. In order to know which of ipv4/ipv6
and udp/tcp one will need to use respectively net_pkt_family(pkt) and
net_context_get_ip_proto(context).
Having access to those headers directly, many callbacks will not need
to parse the packet again no get the src/dst addresses or the src/dst
ports. This will be change after this commit.
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>