system/uorb: fix err when using the -n 1 parameter

Signed-off-by: fangpeina <fangpeina@xiaomi.com>

system/uorb/listener.c

@@ -535,12 +535,7 @@ static void listener_monitor(FAR struct list_node *objlist, int nb_objects,
           fds[i].events = POLLIN;
         }
 
-      if (nb_msgs == 1)
-        {
-          listener_print(tmp->object.meta, fd);
-          orb_unsubscribe(fd);
-        }
-      else if (interval != 0)
+      if (interval != 0)
         {
           orb_set_interval(fd, (unsigned)interval);
 
@@ -553,13 +548,6 @@ static void listener_monitor(FAR struct list_node *objlist, int nb_objects,
       i++;
     }
 
-  if (nb_msgs == 1)
-    {
-      free(fds);
-      free(recv_msgs);
-      return;
-    }
-
   /* Loop poll and print recieved messages */
 
   while ((!nb_msgs || nb_recv_msgs < nb_msgs) && !g_should_exit)