Staging: comedi: add cb_pcidda driver

Driver for the ComputerBoards / MeasurementComputing PCI-DDA series.

From: Ivan Martinez <ivanmr@altavista.com>
Cc: David Schleef <ds@schleef.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>