crypto: sun8i-ce - save hash buffers and dma info to request context

Similar to sun8i-ce skcipher code, move all request-specific data to
request context. This simplifies sun8i_ce_hash_run() and it eliminates
the remaining kmalloc() calls from the digest path.

Since the 'result' buffer in the request ctx struct is used for from-device
DMA, it needs to be properly aligned to CRYPTO_DMA_ALIGN. Therefore:
- increase reqsize by CRYPTO_DMA_PADDING
- add __aligned(CRYPTO_DMA_ALIGN) attribute for the 'result' buffer
- convert all ahash_request_ctx_dma() calls to ahash_request_ctx_dma()

Signed-off-by: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>