netlink: fix the warning introduced by netlink API replacement

Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ieee802154/netlink.c

@@ -64,8 +64,8 @@ struct sk_buff *ieee802154_nl_create(int flags, u8 req)
 
 int ieee802154_nl_mcast(struct sk_buff *msg, unsigned int group)
 {
-	/* XXX: nlh is right at the start of msg */
-	void *hdr = genlmsg_data(nlmsg_data(msg->data));
+	struct nlmsghdr *nlh = nlmsg_hdr(msg);
+	void *hdr = genlmsg_data(nlmsg_data(nlh));
 
 	if (genlmsg_end(msg, hdr) < 0)
 		goto out;
@@ -97,8 +97,8 @@ struct sk_buff *ieee802154_nl_new_reply(struct genl_info *info,
 
 int ieee802154_nl_reply(struct sk_buff *msg, struct genl_info *info)
 {
-	/* XXX: nlh is right at the start of msg */
-	void *hdr = genlmsg_data(nlmsg_data(msg->data));
+	struct nlmsghdr *nlh = nlmsg_hdr(msg);
+	void *hdr = genlmsg_data(nlmsg_data(nlh));
 
 	if (genlmsg_end(msg, hdr) < 0)
 		goto out;