[INET]: Use list_head-s in inetpeer.c

The inetpeer.c tracks the LRU list of inet_perr-s, but makes
it by hands. Use the list_head-s for this.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/net/inetpeer.h
Simple merge

diff --cc net/ipv4/inetpeer.c
Simple merge