platform/x86: huawei-wmi: Add fn-lock support

Huawei Matebook laptops uses Fn key and toggle to access F1-F12 keys.
Along with that, there is this feature called fn-lock that inverts the
behavior of this Fn key and the F1-F12 row.

Signed-off-by: Ayman Bagabas <ayman.bagabas@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>