[FSDP][Easy] Fix 0-dim tensor optim state device (#75243)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/75243
Test Plan: Imported from OSS
Reviewed By: rohan-varma
Differential Revision: D35384883
Pulled By: awgu
fbshipit-source-id: 8dfc12035b79861df093d5921ed7b36050c9f3a0
(cherry picked from commit 699146735d5f87b439940373b16e8188cd958d8b)
