tracing: Make tracing_init_dentry_tr() static

tracing_init_dentry_tr() is not used outside of trace.c, it should
be static.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -5815,7 +5815,7 @@ static __init int register_snapshot_cmd(void)
 static inline __init int register_snapshot_cmd(void) { return 0; }
 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
+static struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
 {
 	if (tr->dir)
 		return tr->dir;

kernel/trace/trace.h

@@ -542,7 +542,6 @@ struct dentry *trace_create_file(const char *name,
 				 void *data,
 				 const struct file_operations *fops);
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr);
 struct dentry *tracing_init_dentry(void);
 
 struct ring_buffer_event;