audit: pass int* to nlmsg_next

Commit 94191213 replaced the macros
NLMSG_NEXT with calls to nlmsg_next which produces this warning:

kernel/audit.c: In function ‘audit_receive_skb’:
kernel/audit.c:928:3: warning: passing argument 2 of ‘nlmsg_next’ makes pointer from integer without a cast
In file included from include/net/rtnetlink.h:5:0,
                 from include/net/neighbour.h:28,
                 from include/net/dst.h:17,
                 from include/net/sock.h:68,
                 from kernel/audit.c:55:
include/net/netlink.h:359:1: note: expected ‘int *’ but argument is of type ‘int’

Fix this by sending the intended pointer.
Signed-off-by: NAlexandru Copot <alex.mihai.c@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kernel/audit.c

@@ -925,7 +925,7 @@ static void audit_receive_skb(struct sk_buff *skb)
 		if (err || (nlh->nlmsg_flags & NLM_F_ACK))
 			netlink_ack(skb, nlh, err);
 
-		nlh = nlmsg_next(nlh, len);
+		nlh = nlmsg_next(nlh, &len);
 	}
 }