[Easy] DDP typo fix (#71607)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71607
Per title
ghstack-source-id: 147577177
Test Plan: N/a
Reviewed By: cbalioglu
Differential Revision: D33694038
fbshipit-source-id: 5a5a618f13bc8b91127169efcebb90b5a36474a1
(cherry picked from commit 62f17f116d8c94f11c93c4d04149bc1e6ab504aa)
