crypto: allwinner - Fix dma_map_sg error check

dma_map_sg return 0 on error.

Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Minghao Chi <chi.minghao@zte.com.cn>
Cc: Peng Wu <wupeng58@huawei.com>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: linux-crypto@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@lists.linux.dev
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>