[TCP]: remove unused argument to cong_avoid op

None of the existing TCP congestion controls use the rtt value pased
in the ca_ops->cong_avoid interface.  Which is lucky because seq_rtt
could have been -1 when handling a duplicate ack.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4e5884a..fec8a7a 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2323,11 +2323,11 @@
 		tcp_ack_no_tstamp(sk, seq_rtt, flag);
 }
 
-static void tcp_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
+static void tcp_cong_avoid(struct sock *sk, u32 ack,
 			   u32 in_flight, int good)
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
-	icsk->icsk_ca_ops->cong_avoid(sk, ack, rtt, in_flight, good);
+	icsk->icsk_ca_ops->cong_avoid(sk, ack, in_flight, good);
 	tcp_sk(sk)->snd_cwnd_stamp = tcp_time_stamp;
 }
 
@@ -2826,11 +2826,11 @@
 		/* Advance CWND, if state allows this. */
 		if ((flag & FLAG_DATA_ACKED) && !frto_cwnd &&
 		    tcp_may_raise_cwnd(sk, flag))
-			tcp_cong_avoid(sk, ack,  seq_rtt, prior_in_flight, 0);
+			tcp_cong_avoid(sk, ack, prior_in_flight, 0);
 		tcp_fastretrans_alert(sk, prior_snd_una, prior_packets, flag);
 	} else {
 		if ((flag & FLAG_DATA_ACKED) && !frto_cwnd)
-			tcp_cong_avoid(sk, ack, seq_rtt, prior_in_flight, 1);
+			tcp_cong_avoid(sk, ack, prior_in_flight, 1);
 	}
 
 	if ((flag & FLAG_FORWARD_PROGRESS) || !(flag&FLAG_NOT_DUP))