Fix TPMI for UL retransmissions
If the ul_ri of srs_feedback changes between a UL transmission and a retransmission, we use the TPMI of transmission.
Closes #879 (closed)
Assertion ((*nrOfLayers==1 && srs_feedback->tpmi <= 1) || (*nrOfLayers==2 && srs_feedback->tpmi == 0)) failed!
In compute_precoding_information() /home/user/openairinterface5g/openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c:2896
TPMI 1 is invalid!
Edited by Roberto Louro Magueta