crypto: caam - mark the hardware descriptor as cache line aligned

Mark the hardware descriptor as being cache line aligned; on DMA
incoherent architectures, the hardware descriptor should sit in a
separate cache line from the CPU accessed data to avoid polluting
the caches.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>