ACPICA: Tables: Fix unbalanced table validations.

As acpi_tb_validate_table() returns failure on checksum verification without
doing invalidatation, all its invocations that are not done to a descriptor
stored in acpi_gbl_root_table_list are checked and balanced.

But this is not a real issue as the descritors that have been passed to
acpi_tb_add_table() are all virtual address tables and the validations are in
fact no-op.  The cleanup can ensure that any future extensions made on
acpi_tb_add_table() to allow it to be invoked with physical address tables
will not trigger memory leakage regressions.

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