Staging: comedi: add ni_at_atmio16d driver

Driver for National Instruments AT-MIO16D board

From: Chris R. Baugher <baugher@enteract.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>