Staging: comedi: add contec_pci_dio driver

driver for Contec PIO1616L digital I/O board

From: Stefano Rivoir <s.rivoir@gts.it>
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>