In order for this to work, the correct rfkill index must be specified
with the rfkill-idx option.
It might be possible to auto-detect the corresponding rfkill-idx option,
but I'm not sure if there's a guaranteed mapping between rfkill name and
interface name, as it seems that rfkills should represent phy devices
and not wlan devices.
The rfkill indexes can be found by checking
/sys/class/rfkill/rfkill<IDX>.
