net: constify struct inet6_protocol

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 5c8d737..3907510 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -83,10 +83,6 @@
 static int ip6mr_fill_mroute(struct sk_buff *skb, struct mfc6_cache *c, struct rtmsg *rtm);
 static void mroute_clean_tables(struct net *net);
 
-#ifdef CONFIG_IPV6_PIMSM_V2
-static struct inet6_protocol pim6_protocol;
-#endif
-
 static struct timer_list ipmr_expire_timer;
 
 
@@ -410,7 +406,7 @@
 	return 0;
 }
 
-static struct inet6_protocol pim6_protocol = {
+static const struct inet6_protocol pim6_protocol = {
 	.handler	=	pim6_rcv,
 };