ACPICA: Remove dead AOPOBJ_INVALID check.

Reversion commit 7cb7f45c7fee (Revert "ACPICA: Remove obsolete
acpi_os_validate_address interface") restored a piece of dead code
related to an obselete AOPOBJ_INVALID flag.  Remove that code again.

This helps to reduce source code differences between Linux and ACPICA
upstream.

[rjw: Changelog]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>