crypto: x86/aesni - Update aesni_set_key() to return void

The aesni_set_key() implementation has no error case, yet its prototype
specifies to return an error code.

Modify the function prototype to return void and adjust the related code.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-crypto@vger.kernel.org
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>