With the merge of fix_NR_DLUL_PF, gNB_dlsch_ulsch_scheduler() has no
nb_periods_per_frame variable. There are two changes here:

1) calculate this locally for initializing tdd_beam_association

2) do not pass it into schedule_nr_mib(). Further, use the following:
   nb_periods_per_frame = slots_per_frame / slots_per_period
   slots_per_frame / nb_periods_per_frame =
     = slots_per_frame / (slots_per_frame / slots_per_period)
     = slots_per_period