Fix various issues on ULSCH processing on UE
This MR fixes various issue on ULSCH processing on UE:
- add mutex to protect ul_config_pdu against race condition with multiple threads. Otherwise UE will crash as parameter of subsequent thread will be overwritten: Assertion (Nl>0) failed!In nr_get_E() openairinterface5g/openair1/PHY/NR_TRANSPORT/nr_tbs_tools.c:47
- Fix a logical error that sends obsolete buffer erroneously on UL and causes crash in gNB. In nr_process_mac_pdu: residual UL MAC PDU in 736.19 with length < 0!, pdu_len -69
- Fix a logical error that if FAPI_NR_UL_CONFIG_TYPE_PUSCH pdu is not of index 0 in ul_config->ul_config_list, the packet is not sent out.