The working copy of IV is the same size as the transformation's IV.
It is not necessary to copy more than that from the template since
iv_len is usually less than MAX_IVLEN and the rest of the copied data
is garbage.
Signed-off-by: Cristian Stoica <cristian.stoica@freescale.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>