`aiecc` should reject unknown command-line arguments

`aiecc` currently does not reject unrecognized command-line arguments, e.g., `aiecc --garbage` works without error. I think it should (happy to be convinceed otherwise).  Since some options have been renamed (e.g., `--aie-generate-npu` has been renamed to `--aie-generate-npu-insts`), this causes some silent failures if you use the wrong argument  name.