[NETLINK]: Mark netlink policies const

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index adff4c8..b6eaca1 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -60,7 +60,7 @@
 {
 	u8			cmd;
 	unsigned int		flags;
-	struct nla_policy	*policy;
+	const struct nla_policy	*policy;
 	int		       (*doit)(struct sk_buff *skb,
 				       struct genl_info *info);
 	int		       (*dumpit)(struct sk_buff *skb,