Fixed histc return type for CUDA (#20369)
Summary:
Fixing reported [issue](https://github.com/pytorch/pytorch/issues/20208).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/20369
Reviewed By: zou3519
Differential Revision: D15300959
Pulled By: izdeby
fbshipit-source-id: 219692f99a66ea433112dfc226132eb6867122cf
