Staging: comedi: add icp_multi driver

This adds the icp_multi driver to the tree.

From: Anne Smorthit <anne.smorthit@sfwte.ch>
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>