net: mark net_proto_ops as const

All usages of structure net_proto_ops should be declared const.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 7a58c87..4d30606 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -2325,7 +2325,7 @@
 };
 #endif
 
-static struct net_proto_family	dn_family_ops = {
+static const struct net_proto_family	dn_family_ops = {
 	.family =	AF_DECnet,
 	.create =	dn_create,
 	.owner	=	THIS_MODULE,