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>

drivers/platform/x86/Kconfig

@@ -587,6 +587,20 @@ config EEEPC_WMI
 	  If you have an ACPI-WMI compatible Eee PC laptop (>= 1000), say Y or M
 	  here.
 
+config ASUS_WIRELESS
+	tristate "Asus Wireless Radio Control Driver"
+	depends on ACPI
+	depends on INPUT
+	---help---
+	  The Asus Wireless Radio Control handles the airplane mode hotkey
+	  present on some Asus laptops.
+
+	  Say Y or M here if you have an ASUS notebook with an airplane mode
+	  hotkey.
+
+	  If you choose to compile this driver as a module the module will be
+	  called asus-wireless.
+
 config ACPI_WMI
 	tristate "WMI"
 	depends on ACPI