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/appletalk/ddp.c b/net/appletalk/ddp.c
index b1a4290..abe3801 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1821,7 +1821,7 @@
 #endif
 
 
-static struct net_proto_family atalk_family_ops = {
+static const struct net_proto_family atalk_family_ops = {
 	.family		= PF_APPLETALK,
 	.create		= atalk_create,
 	.owner		= THIS_MODULE,