staging:serqt_usb2: Fix sparse warning restricted __le16 degrades to integer

This patch fixes the following sparse warning :
drivers/staging/serqt_usb2/serqt_usb2.c:727:40: warning: restricted __le16 degrades to integer
Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/serqt_usb2/serqt_usb2.c

@@ -724,7 +724,7 @@ static int qt_startup(struct usb_serial *serial)
 		goto startup_error;
 	}
 
-	switch (serial->dev->descriptor.idProduct) {
+	switch (le16_to_cpu(serial->dev->descriptor.idProduct)) {
 	case QUATECH_DSU100:
 	case QUATECH_QSU100:
 	case QUATECH_ESU100A: