ideapad: add Lenovo IdeaPad Z570 support (part 1)

The patch adds support for Lenovo IdeaPad Z570 laptop. It makes all special
keys working, adds possibility to control fan like Windows does, controls
Touchpad Disabled LED, toggles touchpad state via keyboard controller and
corrects touchpad behavior on resume from suspend. It is new, modified
version of patch. Now it does not depend on psmouse and does not need patching
of input subsystem.

Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>

This is part 1 for special button handling.

Signed-off-by: Ike Panhc <ike.pan@canonical.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>