Staging: comedi: add ni_pcidio driver

Driver for National Instruments PCI-DIO-96/PCI-6508, PCI-DIO-32HS, and
PCI-6503 cards.

From: 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>