Staging: comedi: add pcl818 driver

For Advantech cards:
	PCL-818L, PCL-818H, PCL-818HD, PCL-818HG, PCL-818, PCL-718

From: Michal Dobes <dobes@tesnet.cz>
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>