crypto: sun8i-ss - fix description of stat_fb

The description of stat_fb was wrong, let's fix it.

Fixes: f08fcced ("crypto: allwinner - Add sun8i-ss cryptographic offloader")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>