crypto: arm64/sm4-ce - check for the right CPU feature bit

ARMv8.2 specifies special instructions for the SM3 cryptographic hash
and the SM4 symmetric cipher. While it is unlikely that a core would
implement one and not the other, we should only use SM4 instructions
if the SM4 CPU feature bit is set, and we currently check the SM3
feature bit instead. So fix that.

Fixes: e99ce921 ("crypto: arm64 - add support for SM4...")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>