crypto: sun8i-ce - fix comparison of integer expressions of different signedness

This patch fixes the warning:
warning: comparison of integer expressions of different signedness: 'int' and 'long unsigned int' [-Wsign-compare]

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>