crypto: sun8i-ss - Remove GFP_DMA and add DMA alignment padding

GFP_DMA does not guarantee that the returned memory is aligned
for DMA.  In fact for sun8i-ss it is superfluous and can be removed.

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>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>