debugfs: debugfs_use_start/finish do not exist anymore

debugfs_use_file_start() and debugfs_use_file_finish() do not exist
since commit c9afbec2 ("debugfs: purge obsolete SRCU based removal
protection"); tweak debugfs_create_file_unsafe() comment.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/debugfs/inode.c

@@ -422,8 +422,8 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
  * debugfs core.
  *
  * It is your responsibility to protect your struct file_operation
- * methods against file removals by means of debugfs_use_file_start()
- * and debugfs_use_file_finish(). ->open() is still protected by
+ * methods against file removals by means of debugfs_file_get()
+ * and debugfs_file_put(). ->open() is still protected by
  * debugfs though.
  *
  * Any struct file_operations defined by means of