[IPV6]: Protect RTM_GETRULE table entry with IPV6_MULTIPLE_TABLES ifdef

This is how IPv4 handles this case too.

Based upon a patch from Andrew Morton.
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -3529,7 +3529,9 @@ static struct rtnetlink_link inet6_rtnetlink_table[RTM_NR_MSGTYPES] = {
 	[RTM_DELROUTE - RTM_BASE] = { .doit	= inet6_rtm_delroute, },
 	[RTM_GETROUTE - RTM_BASE] = { .doit	= inet6_rtm_getroute,
 				      .dumpit	= inet6_dump_fib, },
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
 	[RTM_GETRULE  - RTM_BASE] = { .dumpit   = fib6_rules_dump,   },
+#endif
 };
 
 static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)