ACPI / proc: Do not say when /proc interfaces will be deleted in Kconfig

ACPI / proc: Do not say when /proc interfaces will be deleted in Kconfig

Do not tell people in the Kconfig help when exactly we are going to
remove the deprecated ACPI interfaces in /proc, because, honestly,
we don't know.  We will remove them when they are not used any more.

In particular, do not tell them that the interfaces will be removed
in a kernel release that already happened long ago.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>