fixing layer_norm cuda bug (#69210)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/69208
Pull Request resolved: https://github.com/pytorch/pytorch/pull/69210
Reviewed By: H-Huang
Differential Revision: D32764811
Pulled By: ngimel
fbshipit-source-id: fb4201fe5f2284fcb22e36bc1029eef4a21b09bf
