pc/wifi: prevent calling driver from pthread

Querying the RFKILL state led to execution of the Lx_kit::scheduler by
the pthread running the wpa_supplicant. As this may not happen the
RFKILL state is now solely managed by the driver and only the cached
state is read by the supplicant.

Fixes #4537.

repos/dde_linux/include/wifi/rfkill.h

@@ -21,6 +21,5 @@ namespace Wifi {
 }
 
 bool wifi_get_rfkill(void);
-void wifi_set_rfkill(bool);
 
 #endif /* _WIFI__RFKILL_H_ */