use optimized cpu op lib (#2156)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/2156

ghstack-source-id: 216889055
exported-using-ghexport

validated oss ci is clean. have to by pass because ci think its needs internal linter to pass.
bypass-github-export-checks

Reviewed By: mergennachin

Differential Revision: D54198223

fbshipit-source-id: 0ab0b63cd80b3bae1e1dc110d74baed4b9500f85