Fix pynvml (#2553)
Summary:
Fix https://github.com/pytorch/benchmark/issues/2552
Require `pynvml>=12.0.0`.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/2553
Reviewed By: xuzhao9
Differential Revision: D66792733
Pulled By: FindHao
fbshipit-source-id: 1e7ed65db13bd592cbbd70dcd38cca740d3eaf26
