Let the user tells if BLED and WLED should be exposed as led or
rfkill (the old sysfs are still here, but this adds a standard
interface to control the device).

For example on my A6JC, with WAPF=1, I would do:

$ modprobe asus-laptop wled_type=led bluetooth_type=rfkill

There is still no known way to automatically guess what BLED
and WLED methods will control, it's why user information is needed.

A userspace database could do that automatically, and maybe some DMI
matching in the driver.
Signed-off-by: NCorentin Chary <corentin.chary@gmail.com>
Signed-off-by: NMatthew Garrett <mjg@redhat.com>