pytorch

65bfcde0 - Use c10::variant-based enums for SmoothL1Loss module and functional

Use c10::variant-based enums for SmoothL1Loss module and functional Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/29536 Test Plan: Imported from OSS Differential Revision: D18432272 Pulled By: yf225 fbshipit-source-id: fa355145962e93025b7de98b99b0a4fc82e8c871