Slave RU can now synchronize, the problem was in nb_antennas_rx which is init...

Slave RU can now synchronize, the problem was in nb_antennas_rx which is init in UE but not in RU. I added it in ru_thread_control, but it should be done somewhere else. Added msg RRU_sync_ok from RRU to RAU to inform the RAU that the RRU is in sync