platform/x86: Add Asus Wireless Radio Control driver

Some Asus notebooks like the Asus E202SA and the Asus X555UB have a
separate ACPI device for notifications from the airplane mode hotkey.
This device is called "Wireless Radio Control" in Asus websites and ASHS
in the DSDT, and its ACPI _HID is ATK4002 in the two models mentioned
above.

For these models, when the airplane mode hotkey (Fn+F2) is pressed, a
query 0x0B is started in the Embedded Controller, and all this query does
is a notify ASHS with the value 0x88 (for acpi_osi >= "Windows 2012"):

	Scope (_SB.PCI0.SBRG.EC0)
	{
		(...)
		Method (_Q0B, 0, NotSerialized)  // _Qxx: EC Query
		{
			If ((MSOS () >= OSW8))
			{
				Notify (ASHS, 0x88) // Device-Specific
			}
			Else
			{
				(...)
			}
		}
	}

Signed-off-by: João Paulo Rechi Vita <jprvita@endlessm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>