crypto: caam - fix DMA mapping dir for generated IV

In case of GIVCIPHER, IV is generated by the device.
Fix the DMA mapping direction.

Cc: <stable@vger.kernel.org> # 3.19+
Fixes: 7222d1a3

 ("crypto: caam - add support for givencrypt cbc(aes) and rfc3686(ctr(aes))")
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>