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 <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]

Signed-off-by: Jack Wang <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/sahara.c

···
 
 	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;
 	}