[IPV6] ROUTE: Assign rt6i_idev for ip6_{prohibit,blk_hole}_entry.

I think this is less critical, but is also suitable for -stable
release.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -4204,6 +4204,10 @@ int __init addrconf_init(void)
 		return err;
 
 	ip6_null_entry.rt6i_idev = in6_dev_get(&loopback_dev);
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	ip6_prohibit_entry.rt6i_idev = in6_dev_get(&loopback_dev);
+	ip6_blk_hole_entry.rt6i_idev = in6_dev_get(&loopback_dev);
+#endif
 
 	register_netdevice_notifier(&ipv6_dev_notf);