crypto: caam - fix rfc4106 encap shared descriptor

The encap shared descriptor was changed to use the new IV convention.
In the process some commands were shifted, making the output length
zero, caam effectively writing garbage in dst.

While here, update the decap descriptor to execute the "write" commands
before the "read"s (as it previously was).
This makes sure the input fifo is drained before becoming full.

Fixes: 46218750

 ("crypto: caam - Use new IV convention")
Signed-off-by: Horia Geant? <horia.geanta@freescale.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>