staging: visorutil driver to provide common functionality to other s-Par drivers

The visorutil module is a support library required by all other s-Par
driver modules. Among its features it abstracts reading, writing, and
manipulating a block of memory.

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