crypto: sa2ul - Select CRYPTO_AUTHENC

The sa2ul driver uses crypto_authenc_extractkeys and therefore
must select CRYPTO_AUTHENC.

Fixes: 7694b6ca

 ("crypto: sa2ul - Add crypto driver")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>