misc: add HP WMI laptop extras driver

This driver adds support for reading and configuring certain information
on modern HP laptops with WMI BIOS interfaces.  It supports enabling and
disabling the ambient light sensor, querying attached displays and hard
drive temperature, sending events on docking and querying the state of the
dock and toggling the state of the wifi, bluetooth and wwan hardware via
rfkill.  It also makes the little "(i)" button work on machines that send
that via WMI rather than via the keyboard controller.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>