staging: visorchannel module

The visorchannel module is a support library that abstracts reading
and writing a channel in memory.

Signed-off-by: Ken Cox <jkc@redhat.com>
Cc: Ben Romer <sparmaintainer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>