ipv6/addrconf: common code located

$ codiff net/ipv6/addrconf.o net/ipv6/addrconf.o.new
net/ipv6/addrconf.c:
 addrconf_notify | -267
1 function changed, 267 bytes removed

net/ipv6/addrconf.c:
 add_addr |  +86
1 function changed, 86 bytes added

net/ipv6/addrconf.o.new:
2 functions changed, 86 bytes added, 267 bytes removed, diff: -181

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>