[clang] [llvm] [ARM] Emit an error when the hard-float ABI is enabled but can't be used. (PR #111334)

[Chris Copeland via cfe-commits]

chrisnc wrote:

clang tests are passing now, but some llvm tests are not, e.g., invocations of llc in `CodeGen/ARM/arm-eabi.ll` that specify e.g., `--target=arm-none-eabihf` don't include enough features to actually use eabihf. Any suggestions on the right place to address this would be appreciated.

https://github.com/llvm/llvm-project/pull/111334