Currently, NR PDCP ticks are active only with monolithic gNB, triggered by the MAC scheduler in gNB_scheduler.c.
In F1 split mode, as there is no MAC, there’s no source to advance the NR PDCP timer via "nr_pdcp_wakeup_timer_thread()".
This commit introduces a dedicated thread for NR PDCP ticks in gNB-CU and CU-UP mode.
Without it, packet losses at the F1 uplink would cause indefinite buffering, as t-Reordering won't expire due to the lack of NR PDCP timer ticks.

Integration: `2024.w38`

See merge request oai/openairinterface5g!2970

* !2932 Minor: Set correct USRP flags when not transmitting
* !2961 prevent UE to declare RLF in phy-test mode
* !2962 prevent UE to print HARQ processing error log for MSG2
* !2958 Automatic selection of SSB bitmap length
* !2967 bugfix: reject malformed rrcSetupComplete message
* !2947 Add 5G/NR MAC documentation
* !2959 nr rlc: fix standalone tests

Integration Branch : 2024 Week 36

See merge request oai/openairinterface5g!2956

Flags are set to INVALID when it is not a UL slot. This is important
when using GPIO to control TRX switch.

./run_tests.sh was not functional anymore because of the introduction
of AssertFatal() in nr_rlc_entity.c

Including the .h and providing exit_function() solves the problem.

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Co-authored-by: Luis Pereira <lpereira@allbesmart.pt>

Co-authored-by: Luis Pereira <lpereira@allbesmart.pt>

The F1AP UE context release procedure can happen in at least two cases:

1. core requested a release of a UE
2. CU requests DU a release of a UE without a core release (e.g.,
   handover)

In case 1., the CU has to fully release the UE in the CU, then ack the
NGAP message from the core, whilst in 2., nothing of that should happen
after the DU acknowledges the F1AP UE context release cmd.

In some cases, we don't have the ue_data that is used until this commit.
Make this macro more general by only requiring the assoc_id to check.