crypto: sun8i-ss - fix result memory leak on error path

This patch fixes a memory leak on an error path.

Fixes: d9b45418

 ("crypto: sun8i-ss - support hash algorithms")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>