crypto: marvell/cesa - fix test in mv_cesa_dev_dma_init()

We are checking twice if dma->cache_pool is not NULL but are never testing
dma->padding_pool value.

Cc: stable@vger.kernel.org
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>