acer-wmi: Add driver for newer Acer laptops

acer-wmi: Add driver for newer Acer laptops

This is a driver for newer Acer (and Wistron) laptops. It adds wireless
radio and bluetooth control, and on some laptops, exposes the mail LED and
LCD backlight.

v1:

* Initial release

v2:

* Replace left over ACPI references with WMI
* Add GUID based autoloading (depends on future work to WMI)
* Add DMI based autoloading (backup solution until WMI sysfs/ class
  work is available)
* Checkpatch fixes

v3:

* Add new EC quirks for Aspire 3100 & 5100, and Extensa 5220

v4:

* Simplified internal handling of WMID and AMW0 devices
* Add autodetection for bluetooth and maximum brightness on AMW0 V2 and
  WMID laptops.

v5:

* Add EC quirk for Medion MD 98000
* Add autodetection for AMW0, and mail LED on AMW0 and AMW0 V2.
* Improve error handling
* Fix AMW0 V2 bluetooth and wireless, by using both WMID and AMW0 methods
  to ensure that the correct value is always set.

v6:

* Fix 'use before initialisation' bug with quirks.

v7

* Fix bug on AMW0 where acer-wmi would exit if a mail LED was not
  detected.
* Add Acer Aspire 9110 mail LED support
* Fix section mismatch warnings

Signed-off-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
CC: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Len Brown <len.brown@intel.com>