crypto: crypto4xx - properly set IV after de- and encrypt

This patch fixes cts(cbc(aes)) test when cbc-aes-ppc4xx is used.
alg: skcipher: Test 1 failed (invalid result) on encryption for cts(cbc-aes-ppc4xx)
00000000: 4b 10 75 fc 2f 14 1b 6a 27 35 37 33 d1 b7 70 05
00000010: 97
alg: skcipher: Failed to load transform for cts(cbc(aes)): -2

The CTS cipher mode expect the IV (req->iv) of skcipher_request
to contain the last ciphertext block after the {en,de}crypt
operation is complete.

Fix this issue for the AMCC Crypto4xx hardware engine.
The tcrypt test case for cts(cbc(aes)) is now correctly passed.

name         : cts(cbc(aes))
driver       : cts(cbc-aes-ppc4xx)
module       : cts
priority     : 300
refcnt       : 1
selftest     : passed
internal     : no
type         : skcipher
async        : yes
blocksize    : 16
min keysize  : 16
max keysize  : 32
ivsize       : 16
chunksize    : 16
walksize     : 16

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>