crypto: caam - fix caam_dump_sg that iterates through scatterlist

Fix caam_dump_sg by correctly determining the next scatterlist
entry in the list.

Fixes: 5ecf8ef9

 ("crypto: caam - fix sg dump")
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>