[IPV6]: ROUTE: Add accept_ra_rt_info_max_plen sysctl.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index f49488f..8ad4bea 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -535,6 +535,7 @@
 	NET_IPV6_ACCEPT_RA_PINFO=19,
 	NET_IPV6_ACCEPT_RA_RTR_PREF=20,
 	NET_IPV6_RTR_PROBE_INTERVAL=21,
+	NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN=22,
 	__NET_IPV6_MAX
 };