crypto: Align command descriptors to burst size.

According to the hardware design, Crypto Engine 5.0
hardware expects all descriptors to be burst-size
aligned for performance reasons. In the case of using
descriptors, unaligned addresses have a huge performance
impact. In this case it might cause h/w to take longer
processing times when compared to the crypto driver directly
setting the registers via processor.

Signed-off-by: Ramesh Masavarapu <rameshm@codeaurora.org>