battery: disable secondary module by default
battery: disable secondary module by default

Avoid a GCS showing 2 battery indicators.
Alternatively we could also check the 'connected' flag, but this is more
explicit.

PX4/Firmware,PX4/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,PX4/Firmware,acfloria/Firmware,krbeverx/Firmware,acfloria/Firmware,acfloria/Firmware,acfloria/Firmware,PX4/Firmware