crypto: talitos - properly handle split ICV.

The driver assumes that the ICV is as a single piece in the last
element of the scatterlist. This assumption is wrong.

This patch ensures that the ICV is properly handled regardless of
the scatterlist layout.

Fixes: 9c4a7965 ("crypto: talitos - Freescale integrated security engine (SEC) driver")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>