staging: unisys: remove visorbus_private.h

visorbus_private.h is only included from visorbus_main.c and has no
other purpose.  The code can be easily moved into visorbus_main.c.

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>