Staging: comedi: add adl_pci7296 driver

Driver for the Adlink PCI-7296 96 ch. digital io board

From: Jon Grierson <jd@renko.co.uk>
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>