[NET]: Make the sk_clone() lighter

The sk_prot_alloc() already performs all the stuff needed by the
sk_clone(). Besides, the sk_prot_alloc() requires almost twice
less arguments than the sk_alloc() does, so call the sk_prot_alloc()
saving the stack a bit.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -976,8 +976,9 @@ void sk_free(struct sock *sk)
 
 struct sock *sk_clone(const struct sock *sk, const gfp_t priority)
 {
-	struct sock *newsk = sk_alloc(sk->sk_net, sk->sk_family, priority, sk->sk_prot, 0);
+	struct sock *newsk;
 
+	newsk = sk_prot_alloc(sk->sk_prot, priority, sk->sk_family);
 	if (newsk != NULL) {
 		struct sk_filter *filter;