netiucv: improve state checking in conn_action_txdone

state checking in conn_action_txdone() is inconsistent.
This patch makes it consistent and issues a trace message
if an unexpected state is detected for the netiucv device.
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/netiucv.c

@@ -739,7 +739,11 @@ static void conn_action_txdone(fsm_instance *fi, int event, void *arg)
 
 	IUCV_DBF_TEXT(trace, 4, __func__);
 
-	if (conn && conn->netdev)
+	if (!conn || !conn->netdev) {
+		IUCV_DBF_TEXT(data, 2,
+			      "Send confirmation for unlinked connection\n");
+		return;
+	}
 	privptr = netdev_priv(conn->netdev);
 	conn->prof.tx_pending--;
 	if (single_flag) {