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

Merge branch 'ru_rau_enhancement' of https://gitlab.eurecom.fr/oai/openairinterface5g into ru_rau_enhancement

MTU tuning removed for now.

Merge branch 'develop-nos1-fixes' of https://gitlab.eurecom.fr/oai/openairinterface5g into develop-nos1-fixes

Includes the following updates:
1. oaisim/lte-softmodem in noS1
2. UE fixes for oaisim
3. IF4p5 fixes (doesn't work on develop)
4. UE fixes for DCI handling (corrects problem introduced in develop)
Conflicts:
	cmake_targets/CMakeLists.txt
	targets/SIMU/USER/oaisim_functions.c

Merge branch 'ru_rau_enhancement' of https://gitlab.eurecom.fr/oai/openairinterface5g into ru_rau_enhancement