Add `torch.version.hip` from cmake (#29815)
Summary:
This adds the HIP_VERSION cmake variable as hip_version.
This should help detecting ROCm, e.g. in https://github.com/pytorch/pytorch/issues/22091.
To parallel CUDA, hip_version is a string.
An alternative variant might be to split by '.' and only take the first two parts.
The method suffers a bit from ROCm not being as monolithic as CUDA.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29815
Differential Revision: D18532267
Pulled By: bddppq
fbshipit-source-id: 1bde4ad0cfacc47bfd1c0945e130921d8575a5bf
