tcp: fix data delivery rate

Now skb->mstamp_skb is updated later, we also need to call
tcp_rate_skb_sent() after the update is done.

Fixes: 8c72c65b426b ("tcp: update skb->skb_mstamp more carefully")
Signed-off-by: Eric Dumazet <[e-mail]>
Acked-by: Soheil Hassas Yeganeh <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/ipv4/tcp_output.c

···
 	if (clone_it) {
 		TCP_SKB_CB(skb)->tx.in_flight = TCP_SKB_CB(skb)->end_seq
 			- tp->snd_una;
-		tcp_rate_skb_sent(sk, skb);
-
 		oskb = skb;
 		if (unlikely(skb_cloned(skb)))
 			skb = pskb_copy(skb, gfp_mask);
···
 		tcp_enter_cwr(sk);
 		err = net_xmit_eval(err);
 	}
-	if (!err && oskb)
+	if (!err && oskb) {
 		oskb->skb_mstamp = tp->tcp_mstamp;
-
+		tcp_rate_skb_sent(sk, oskb);
+	}
 	return err;
 }