ACPI: Revert "ACPI / AC: convert ACPI ac driver to platform bus"

Revert commit cc8ef527 (ACPI / AC: convert ACPI ac driver to
platform bus) that is reported to break thermal management on
MacBook Air 2013 with ArchLinux.

Fixes: cc8ef527 (ACPI / AC: convert ACPI ac driver to platform bus)
References: https://bugzilla.kernel.org/show_bug.cgi?id=71711


Cc: Zhang Rui <rui.zhang@intel.com>
Reported-and-tested-by: Manuel Krause <manuelkrause@netscape.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Cc: 3.13+ <stable@vger.kernel.org> # 3.13+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>