[clang] [llvm] [AMDGPU] Add support for `v_cvt_f16_fp8` on gfx1250 (PR #146302)

[Shilei Tian via llvm-commits]

shiltian wrote:

> > Co-authored-by: Shilei Tian [i at tianshilei.me](mailto:i at tianshilei.me)
> 
> Co authored by yourself?

Yes, because if you check the commit, the author is @rampitec.

https://github.com/llvm/llvm-project/pull/146302