[CMake] Use libtorch_cuda list defined in bzl file (#49429)
Summary:
Since NCCL is an optional CUDA dependency, remove nccl.cpp from the core filelist
Pull Request resolved: https://github.com/pytorch/pytorch/pull/49429
Reviewed By: nikithamalgifb
Differential Revision: D25569883
Pulled By: malfet
fbshipit-source-id: 61371a4c6b0438e4e0a7f094975b9a9f9ffa4032
