ACPI: Drop the second argument of acpi_bus_scan()

After the removal of acpi_start_single_object() and acpi_bus_start()
the second argument of acpi_bus_scan() is not necessary any more,
so drop it and update acpi_bus_check_add() accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>