crypto: caam - Remove GFP_DMA and add DMA alignment padding

GFP_DMA does not guarantee that the returned memory is aligned
for DMA. It should be removed where it is superfluous.

However, kmalloc may start returning DMA-unaligned memory in future
so fix this by adding the alignment by hand.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: caam/rng - Add support for PRNG

Add support for random number generation using PRNG
mode of CAAM and expose the interface through crypto API.

According to the RM, the HW implementation of the DRBG follows
NIST SP 800-90A specification for DRBG_Hash SHA-256 function

Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Reviewed-by: Horia Geant <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>