USB: serial: pl2303: add new ATEN device id

This adds a new ATEN device id for a new pl2303-based device.

Reported-by: Peter Kuo <PeterKuo@aten.com.tw>
Cc: stable <stable@vger.kernel.org>
Cc: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>