ndisc: Add missing strategies for per-device retrans timer/reachable time settings.

Noticed from Al Viro <viro@ftp.linux.org.uk> via David Miller
<davem@davemloft.net>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index e591e09..8dd9155 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4242,7 +4242,7 @@
 	neigh_sysctl_register(idev->dev, idev->nd_parms, NET_IPV6,
 			      NET_IPV6_NEIGH, "ipv6",
 			      &ndisc_ifinfo_sysctl_change,
-			      NULL);
+			      ndisc_ifinfo_sysctl_strategy);
 	__addrconf_sysctl_register(dev_net(idev->dev), idev->dev->name,
 			idev->dev->ifindex, idev, &idev->cnf);
 }