Added out= variant for torch.linalg.lstsq (#54721)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/54721
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D27874711
Pulled By: mruberry
fbshipit-source-id: 696ebb6eb0bad81988e9cb7a081388a3a5ab3e2c
