Remove rssi call on the BLEDevice (#366)

switchbot/devices/device.py

@@ -295,7 +295,7 @@ class SwitchbotBaseDevice:
         """Return RSSI of device."""
         if self._sb_adv_data:
             return self._sb_adv_data.rssi
-        return self._device.rssi
+        return -127
 
     async def _ensure_connected(self):
         """Ensure connection to device is established."""