[llvm] [RISCV] Cost ordered bf16/f16 w/ zvfhmin reductions as invalid (PR #114250)

[Harald van Dijk via llvm-commits]

hvdijk wrote:

The process is the same, the process for cherry-picking a PR relies on identifying the commit after merging and cherry-picking that anyway :) I'll do that.

https://github.com/llvm/llvm-project/pull/114250