Add 9.0a to cpp_extension supported compute archs (#110587)
There's an extended compute capability 9.0a for Hopper that was introduced in Cuda 12.0: https://docs.nvidia.com/cuda/archive/12.0.0/cuda-compiler-driver-nvcc/index.html#gpu-feature-list
E.g. Cutlass leverages it: https://github.com/NVIDIA/cutlass/blob/5f13dcad781284678edafa3b8d108120cfc6a6e4/python/cutlass/emit/pytorch.py#L684
This adds it to the list of permitted architectures to use in `cpp_extension` directly.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/110587
Approved by: https://github.com/ezyang
