USB: serial: quatech2: fix control-request directions

The direction of the pipe argument must match the request-type direction
bit or control requests may fail depending on the host-controller-driver
implementation.

Fix the three requests which erroneously used usb_rcvctrlpipe().

Fixes: f7a33e60 ("USB: serial: add quatech2 usb to serial driver")
Cc: stable@vger.kernel.org      # 3.5
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/quatech2.c

@@ -416,7 +416,7 @@ static void qt2_close(struct usb_serial_port *port)
 
 	/* flush the port transmit buffer */
 	i = usb_control_msg(serial->dev,
-			    usb_rcvctrlpipe(serial->dev, 0),
+			    usb_sndctrlpipe(serial->dev, 0),
 			    QT2_FLUSH_DEVICE, 0x40, 1,
 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
 
@@ -426,7 +426,7 @@ static void qt2_close(struct usb_serial_port *port)
 
 	/* flush the port receive buffer */
 	i = usb_control_msg(serial->dev,
-			    usb_rcvctrlpipe(serial->dev, 0),
+			    usb_sndctrlpipe(serial->dev, 0),
 			    QT2_FLUSH_DEVICE, 0x40, 0,
 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
 
@@ -639,7 +639,7 @@ static int qt2_attach(struct usb_serial *serial)
 	int status;
 
 	/* power on unit */
-	status = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+	status = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
 				 0xc2, 0x40, 0x8000, 0, NULL, 0,
 				 QT2_USB_TIMEOUT);
 	if (status < 0) {