crypto: talitos - support for assoc data provided as scatterlist

Generate a link table in case assoc data is a scatterlist.
While at it, add support for handling non-contiguous assoc data and iv.
Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>