[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_hybla.c b/net/ipv4/tcp_hybla.c
index e5be351..b3e55cf 100644
--- a/net/ipv4/tcp_hybla.c
+++ b/net/ipv4/tcp_hybla.c
@@ -85,7 +85,7 @@
  *     o Give cwnd a new value based on the model proposed
  *     o remember increments <1
  */
-static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 rtt,
+static void hybla_cong_avoid(struct sock *sk, u32 ack,
 			    u32 in_flight, int flag)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
@@ -103,7 +103,7 @@
 		return;
 
 	if (!ca->hybla_en)
-		return tcp_reno_cong_avoid(sk, ack, rtt, in_flight, flag);
+		return tcp_reno_cong_avoid(sk, ack, in_flight, flag);
 
 	if (ca->rho == 0)
 		hybla_recalc_param(sk);