ACPICA: Fixes for acpiExec namespace init file

ACPICA: Fixes for acpiExec namespace init file

This is the result of squashing the following ACPICA commit ID's:
6803997e5b4f3635cea6610b51ff69e29d251de3
f31cdf8bfda22fe265c1a176d0e33d311c82a7f7

This change fixes several problems with the support for the
acpi_exec namespace init file (-fi option). Specifically, it
fixes AE_ALREADY_EXISTS errors, as well as various seg faults.

Link: https://github.com/acpica/acpica/commit/f31cdf8b
Link: https://github.com/acpica/acpica/commit/6803997e
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>