staging: unisys: move visorchipset files to visorbus

Move visorchipset_main.c and visorchipset.h to visorbus/visorchipset.c and
visorbus/visorbus_private.h.  This leaves an empty visorchipset directory
which can also be destroyed.

As a result of this patch the visorchipset init code now calls the
visorbus_init() directly.  Similarily the visorchipset exit code now
cleans up by calling visorbus_exit().

No other functional changes were made.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>