acer-wmi: remove threeg and interface sysfs interfaces

acer-wmi: remove threeg and interface sysfs interfaces

Since v3.0 kernel, acer-wmi driver auto detects internal 3G device and
provides the threeg rfkill interface. So the sysfs interface of 3G is
no longer necessary now.

The 7b8aca65 patch added kernel information log to remind to user space
for the threeg sysfs interface will be removed in 2012, then b58b9ffc patch
updated the interface removing time to 2014.

I think the 3 years lead time is enough for user space application to use
rfkill instead of sysfs interface to control 3G device.

This patch removes code about threeg sysfs interface. And it also removes the
unused interface sysfs that exposes which ACPI-WMI method used by acer-wmi
driver on the machine. The information is already exposed by the acer-wmi
initial log.

Cc: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Martin Kepplinger <martink@posteo.de>
Cc: Darren Hart <dvhart@infradead.org>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>