Staging: comedi: add addi-data drivers

This adds the addi-data family of comedi drivers to the staging tree

From: ADDI-DATA GmbH <info@addi-data.com>
Cc: David Schleef <ds@schleef.org>
Cc: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>