[c2] register cuda op for LpNorm (fallback) (#38517)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/38517
as title
Test Plan: buck test
Reviewed By: olittle
Differential Revision: D21562485
fbshipit-source-id: 573419e5a8dae4121d99d5b72ed3960a92db7a54
