crypto: sahara - Fix error check for dma_map_sg

dma_map_sg return 0 on error, it returns the number of
DMA address segments mapped (this may be shorter
than <nents> passed in if some elements of the scatter/gather
list are physically or virtually adjacent and an IOMMU maps
them with a single entry).

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
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>

drivers/crypto/sahara.c

@@ -487,13 +487,13 @@ static int sahara_hw_descriptor_create(struct sahara_dev *dev)
 
 	ret = dma_map_sg(dev->device, dev->in_sg, dev->nb_in_sg,
 			 DMA_TO_DEVICE);
-	if (ret != dev->nb_in_sg) {
+	if (!ret) {
 		dev_err(dev->device, "couldn't map in sg\n");
 		goto unmap_in;
 	}
 	ret = dma_map_sg(dev->device, dev->out_sg, dev->nb_out_sg,
 			 DMA_FROM_DEVICE);
-	if (ret != dev->nb_out_sg) {
+	if (!ret) {
 		dev_err(dev->device, "couldn't map out sg\n");
 		goto unmap_out;
 	}