USB: serial: ftdi_sio: add support for Brainboxes US-159/235/320

commit fbb9b194 upstream.

This patch adds support for the Brainboxes US-159, US-235 and US-320
USB-to-Serial devices.

Signed-off-by: Cameron Williams <cang1@live.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>