staging: comedi: pcl724: add support for Diamond Systems ONYX-MM-DIO module

The Diamond Systems ONYX-MM-DIO board is a PC/104 module with two 8255
chips providing 48 digital I/O channels.

This board can be supported by the pcl724 driver.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>