net: kill arp_ifinit2

It is used in sys/netinet/ip_carp.c by CARP[1][2] protocol which we do not
support it now and have very little chance to support it in the future.

[1] http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/carp.html
[2] http://www.freebsd.org/cgi/man.cgi?query=carp&sektion=4&n=1

Signed-off-by: Asias He <asias@cloudius-systems.com>
debug
debug
trace_in_lltable_lookup

Signed-off-by: Asias He <asias@cloudius-systems.com>