ACPI spec defines ACPI Ambient Light Sensor device (hid ACPI0008),
which provides a standard interface by which the OS may query properties
of the ambient light environment the system is currently operating in,
as well as the ability to detect meaningful changes in these values when
the environment changes.

This patch introduces the ACPI ALS device driver.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>