crypto: sun4i-ss - move from ablkcipher to skcipher API

Update the sun4i-ss driver to use the skcipher API instead of the old
ablkcipher one. It's a bit more tricky than s/ablkcipher/skcipher/, but
still nothing special and the driver's logic stays the same.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>