explicitly provide memory format when calling to clone() at SpectralOps.cu
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/28667
Test Plan: Imported from OSS
Differential Revision: D18333358
Pulled By: ifedan
fbshipit-source-id: 6e5d035517e2b9de811c80ec8255dafceb1a511e
