Decode pfsync packets on network interfaces

[email_luiz.eng.br]

Summary

Looks like when print-ip-demux.c was introduced on ee67461e, the pfsync_ip_print function was missed, causing tcpdump to treat pfsync packets on network interfaces as an unknown protocol.

Sponsored by: InnoGames GmbH

Test Plan

make -C /usr/src/usr.sbin/tcpdump clean
make -C /usr/src/usr.sbin/tcpdump
make -C /usr/src/usr.sbin/tcpdump install
tcpdump -i vtnet0 'ip[9:1]==0xf0' or 'ip6[6:1]==0xf0'

The output should show packets properly decoded instead of this:

14:13:58.861597 IP 192.0.0.1 > 192.0.0.2:  ip-proto-240 216
14:13:58.861618 IP 192.0.0.1 > 192.0.0.2:  ip-proto-240 300
14:13:58.954208 IP 192.0.0.1 > 192.0.0.2:  ip-proto-240 132

[email_luiz.eng.br]

I enclosed the code with a #ifdef HAVE_NET_IF_PFLOG_H to allow for building with WITHOUT_PF=1