Input: xpad - use correct product id for x360w controllers

currently the controllers get the same product id as the wireless
receiver. However the controllers actually have their own product id.

The patch makes the driver expose the same product id as the windows
driver.

This improves compatibility when running applications with WINE.

see https://github.com/paroj/xpad/issues/54

Signed-off-by: Pavel Rojtberg <rojtberg@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>