[llvm] [AMDGPU][True16][CodeGen] fp conversion in true/fake16 format (PR #101678)

[Brox Chen via llvm-commits]

broxigarchen wrote:

> > It seems this patch is missing MC level changes. reduce this PR into CodeGen only and open another PR for MC level changes #104510
> 
> Waiting for the MC PR to be merged, then I will update this PR. Thanks!

It takes a while but this PR is ready for review now. Thanks!

https://github.com/llvm/llvm-project/pull/101678