[TCP]: Remove unnecessary wrapper tcp_packets_out_dec

Makes caller side more obvious, there's no need to have
a wrapper for this oneliner!

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index a367917..1d65ce1 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1735,7 +1735,7 @@
 		 * it is better to underestimate fackets.
 		 */
 		tcp_dec_pcount_approx(&tp->fackets_out, next_skb);
-		tcp_packets_out_dec(tp, next_skb);
+		tp->packets_out -= tcp_skb_pcount(next_skb);
 		sk_stream_free_skb(sk, next_skb);
 	}
 }