Mark cudaGetLastError return value unused in C10_CUDA_CHECK
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/17605
Reviewed By: xw285cornell
Differential Revision: D14277586
Pulled By: bddppq
fbshipit-source-id: 38879208f2ab83cf39d8a8a61b288cd09fcafd9a
