The DCP driver does not obey cryptlen, when doing android CTS this
results in passing to hardware input stream lengths which are not
multiple of block size.

Add a check to prevent future erroneous stream lengths from reaching the
hardware and adjust the scatterlist walking code to obey cryptlen.

Also properly copy-out the IV for chaining.
Signed-off-by: Radu Solea <radu.solea@nxp.com>
Signed-off-by: Franck LENORMAND <franck.lenormand@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>