Replaced usleep with semaphore for current_sfn_sf

targets/RT/USER/lte-ue.c

@@ -1043,7 +1043,11 @@ static void *UE_phy_stub_standalone_pnf_task(void *arg)
     bool sent_any = false;
     int sfn_sf = current_sfn_sf;
     if (sfn_sf == last_sfn_sf) {
-      usleep(100);
+      if (sem_wait(&sfn_semaphore) != 0)
+      {
+        LOG_E(MAC, "sem_wait() error\n");
+        abort();
+      }
       continue;
     }
 

targets/RT/USER/lte-uesoftmodem.c

@@ -733,7 +733,15 @@ int main( int argc, char **argv ) {
     init_queue(&tx_req_pdu_queue);
     init_queue(&hi_dci0_req_queue);
     init_queue(&ul_config_req_queue);
+
     config_sync_var=0;
+    
+    if (sem_init(&sfn_semaphore, 0, 0) != 0)
+    {
+      LOG_E(MAC, "sem_init() error\n");
+      abort();
+    }
+    
     init_UE_stub_single_thread(NB_UE_INST,eMBMS_active,uecap_xer_in,emul_iface);
     init_UE_standalone_thread();
   } else {