Add a missing symbol export that prevents this code to be built as a
module. Also, move the round constant table to the .rodata section,
and use a more optimized version of the core transform.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>