[clang] [llvm] [NVPTX] Add conversion intrinsics from/to fp8 types (e4m3, e5m2) (PR #102969)

[Artem Belevich via cfe-commits]

Artem-B wrote:

Looks like that it was clang-format check github was waiting on an approaval for. I've just clicked that button, let's see what it brings.
The patch is good to go otherwise, IMO.

https://github.com/llvm/llvm-project/pull/102969