Refactor to call post-processor in place

Remove sched_ctrl->sched_ulsch, and call the post-processing function
post_process_ulsch() in the places where sched_ctrl->sched_ulsch has
been assigned. This will have two effects:

- it is not necessary to have the final loop over all UEs, which might
  be costly especially towards many UEs.
- till now, there is only a single sched_ulsch; however, a later commit
  will allow to schedule multiple PUSCH transmissions from a single (DL)
  slot. This would require to make sched_ctrl->sched_ulsch, and
  also iterate through all sched_ulsch. In this new scheme, we can
  simply call post_process_ulsch() multiple times, which is simpler (and
  therefore, implicitly handleded as of this commit).

openair2/E2AP/RAN_FUNCTION/CUSTOMIZED/ran_func_mac.c

@@ -66,7 +66,7 @@ bool read_mac_sm(void* data)
     }
     if (is_ul_slot(rd->slot, &RC.nrmac[mod_id]->frame_structure)) {
       rd->ul_curr_tbs = UE->mac_stats.ul.current_bytes;
-      rd->ul_sched_rb = sched_ctrl->sched_pusch.rbSize;
+      rd->ul_sched_rb = UE->mac_stats.ul.current_rbs;
     }
 
     rd->rnti = UE->rnti;