crypto: rockchip - rename ablk functions to cipher

Some functions have still ablk in their name even if there are
not handling ablk_cipher anymore.
So let's rename them.

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