ACPI: procfs: Remove last dirs after being marked deprecated for a decade

This code is outdated and has been deprecated for a long time, so user
space is not expected to rely on it any more on any systems that are
up to date by any reasonable measure.  Remove it.

Signed-off-by: Thomas Renninger <trenn@suse.de>
[ rjw: Subject / changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>