[clang] [llvm] [LLVM] Add intrinsics for v_cvt_pk_norm_{i16, u16}_f16 (PR #135631)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Looks like the undefs are causing some issues. Presumably that's deliberate here? (So we should ignore the failure?)

These cases should just use poison 

https://github.com/llvm/llvm-project/pull/135631