USB: mct_u232: Fix incorrect TIOCMSET return

The low level helper returns 1 on success. The ioctl should however return
0. As this is the only user of the helper return, make the helper return 0 or
an error code.

Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=43009
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/mct_u232.c

@@ -309,13 +309,16 @@ static int mct_u232_set_modem_ctrl(struct usb_serial *serial,
 			MCT_U232_SET_REQUEST_TYPE,
 			0, 0, buf, MCT_U232_SET_MODEM_CTRL_SIZE,
 			WDR_TIMEOUT);
-	if (rc < 0)
-		dev_err(&serial->dev->dev,
-			"Set MODEM CTRL 0x%x failed (error = %d)\n", mcr, rc);
+	kfree(buf);
+
 	dbg("set_modem_ctrl: state=0x%x ==> mcr=0x%x", control_state, mcr);
 
-	kfree(buf);
-	return rc;
+	if (rc < 0) {
+		dev_err(&serial->dev->dev,
+			"Set MODEM CTRL 0x%x failed (error = %d)\n", mcr, rc);
+		return rc;
+	}
+	return 0;
 } /* mct_u232_set_modem_ctrl */
 
 static int mct_u232_get_modem_stat(struct usb_serial *serial,