eeepc-laptop: add base driver

This patch is based on Eric Cooper's work to clean the original asus_acpi
given by Asus.  It's a platform driver (/sys/devices/platform/eeepc/)
wich support:
     - hotkeys - wlan on/off - camera on/off - cardr on/off

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Len Brown <len.brown@intel.com>