DL Phytest preprocessor: schedule only in one slot

The OAI-UE needs to have PUCCH scheduled at least six slots in advance.
Since we do not support this (yet), but assume that two slots are
enough, we schedule the UE only in slot 1 so it has 6 slots until slot 7
to send PUCCH.

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c

@@ -257,6 +257,8 @@ void nr_preprocessor_phytest(module_id_t module_id,
                              frame_t frame,
                              sub_frame_t slot)
 {
+  if (slot != 1)
+    return;
   NR_UE_info_t *UE_info = &RC.nrmac[module_id]->UE_info;
   const int UE_id = 0;
   const int CC_id = 0;