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().