platform/x86: Add Acer Wireless Radio Control driver

New Acer laptops in 2018 will have a separate ACPI device for
notifications from the airplane mode hotkey. The device name in
the DSDT is SMKB and its ACPI _HID is 10251229.

For these models, when the airplane mode hotkey (Fn+F3) pressed,
a query 0x02 is started in the Embedded Controller, and all this
query does is a notify SMKB with the value 0x80.

        Scope (_SB.PCI0.LPCB.EC0)
        {
                (...)
                Method (_Q02, 0, NotSerialized)  // _Qxx: EC Query
                {
                    HKEV (0x2, One)
		    Notify (SMKB, 0x80)	// Status Change
                }
        }

Based on code from asus-wireless

Signed-off-by: Chris Chiu <chiu@endlessm.com>
Reviewed-by: João Paulo Rechi Vita <jprvita@endlessm.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/Kconfig

@@ -36,6 +36,20 @@ config ACER_WMI
 	  If you have an ACPI-WMI compatible Acer/ Wistron laptop, say Y or M
 	  here.
 
+config ACER_WIRELESS
+        tristate "Acer Wireless Radio Control Driver"
+        depends on ACPI
+        depends on INPUT
+        ---help---
+          The Acer Wireless Radio Control handles the airplane mode hotkey
+          present on new Acer laptops.
+
+          Say Y or M here if you have an Acer notebook with an airplane mode
+          hotkey.
+
+          If you choose to compile this driver as a module the module will be
+          called acer-wireless.
+
 config ACERHDF
 	tristate "Acer Aspire One temperature and fan driver"
 	depends on ACPI && THERMAL