USB: serial: cp210x: add new VID/PID for supporting Teraoka AD2000

Teraoka AD2000 uses the CP210x driver, but the chip VID/PID is
customized with 0988/0578. We need the driver to support the new
VID/PID.

Signed-off-by: Chenxin Jin <bg4akv@hotmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>