crypto: crypto4xx - refactor crypto4xx_copy_pkt_to_dst()

This patch refactors the crypto4xx_copy_pkt_to_dst() to use
scatterwalk_map_and_copy() to copy the processed data between
the crypto engine's scatter ring buffer and the destination
specified by the ablkcipher_request.

This also makes the crypto4xx_fill_one_page() function redundant.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>