ACPICA: Prefer ACPI_TO_POINTER() over ACPI_ADD_PTR()

This is more easy to read.

Signed-off-by: Jung-uk Kim <jkim@free_BSD.org>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>