[llvm] [NVPTX] Add family-specific architectures support (PR #141899)

[Artem Belevich via llvm-commits]

https://github.com/Artem-B commented:

Thank you for adding the details on the sm variant ordering, but I think it still needs some editing. I'd find it terribly confusing if I were to read it without prior context.

https://github.com/llvm/llvm-project/pull/141899