staging: unisys: visorbus: get rid of create_bus_type.

Create bus_type was just calling register_bustype. Since we control how
many times we call create_bus_type it was extraneous keeping a counter if
the bus was already registered, so the functions were no longer needed.

Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>