f2fs: add f2fs_destroy_trace_ios to free radix tree

This patch removes radix tree after finishing tracing IOs.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index e6f035c..0e97974 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1272,6 +1272,7 @@
 	destroy_node_manager_caches();
 	destroy_inodecache();
 	kset_unregister(f2fs_kset);
+	f2fs_destroy_trace_ios();
 }
 
 module_init(init_f2fs_fs)