asus-nb-wmi: Asus Notebooks WMI Driver

Introduce a new driver for Asus Notebooks shipped with
a WMI device instead of the old ACPI device. The WMI
device is almost the same as the one present in Eee PC,
but the event guid and the keymap are different.

The keymap comes from asus-laptop module.

On Asus notebooks, when you call the WMI device, you always
need a 64bit buffer, even if you only want to get the state
of a device (tested on a G73).

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Matthew Garrett <mjg@redhat.com>