tracing: A minor cleanup for create_system_filter()

The first two parameters should be reduced to one, as @tr is simply
@dir->tr.

Link: https://lkml.kernel.org/r/20210324205642.65e03248@oasis.local.home
Link: https://lkml.kernel.org/r/20210325163752.128407-1-hqjagain@gmail.comSuggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_events_filter.c

@@ -1750,7 +1750,6 @@ int create_event_filter(struct trace_array *tr,
  * and always remembers @filter_str.
  */
 static int create_system_filter(struct trace_subsystem_dir *dir,
-				struct trace_array *tr,
 				char *filter_str, struct event_filter **filterp)
 {
 	struct filter_parse_error *pe = NULL;
@@ -1758,13 +1757,13 @@ static int create_system_filter(struct trace_subsystem_dir *dir,
 
 	err = create_filter_start(filter_str, true, &pe, filterp);
 	if (!err) {
-		err = process_system_preds(dir, tr, pe, filter_str);
+		err = process_system_preds(dir, dir->tr, pe, filter_str);
 		if (!err) {
 			/* System filters just show a default message */
 			kfree((*filterp)->filter_string);
 			(*filterp)->filter_string = NULL;
 		} else {
-			append_filter_err(tr, pe, *filterp);
+			append_filter_err(dir->tr, pe, *filterp);
 		}
 	}
 	create_filter_finish(pe);
@@ -1852,7 +1851,7 @@ int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
 		goto out_unlock;
 	}
 
-	err = create_system_filter(dir, tr, filter_string, &filter);
+	err = create_system_filter(dir, filter_string, &filter);
 	if (filter) {
 		/*
 		 * No event actually uses the system filter