simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems

two requirements: no file creations in IS_DEADDIR and no cross-directory
renames whatsoever.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 6638d63..402d022 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -556,7 +556,7 @@ static int init_tracefs(void)
 	return 0;
 
  err:
-	tracefs_remove_recursive(top_dir);
+	tracefs_remove(top_dir);
 	return -ENOMEM;
 }