Migrate CPU clamp to c10::complex (#38460)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/38460
Test Plan: Imported from OSS
Differential Revision: D21663855
Pulled By: anjali411
fbshipit-source-id: 2fa5e17ec12f4eabeb58c5edb8f2459407b1b3f9
