crypto: sun8i-ss - Fix error codes for dma_mapping_error()

If there is a dma_mapping_error() then return negative error codes.
Currently this code returns success.

Fixes: 801b7d57 ("crypto: sun8i-ss - add hmac(sha1)")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/allwinner/sun8i-ss/sun8i-ss-hash.c

@@ -586,7 +586,8 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 			rctx->t_dst[k + 1].len = rctx->t_dst[k].len;
 		}
 		addr_xpad = dma_map_single(ss->dev, tfmctx->ipad, bs, DMA_TO_DEVICE);
-		if (dma_mapping_error(ss->dev, addr_xpad)) {
+		err = dma_mapping_error(ss->dev, addr_xpad);
+		if (err) {
 			dev_err(ss->dev, "Fail to create DMA mapping of ipad\n");
 			goto err_dma_xpad;
 		}
@@ -612,7 +613,8 @@ int sun8i_ss_hash_run(struct crypto_engine *engine, void *breq)
 			goto err_dma_result;
 		}
 		addr_xpad = dma_map_single(ss->dev, tfmctx->opad, bs, DMA_TO_DEVICE);
-		if (dma_mapping_error(ss->dev, addr_xpad)) {
+		err = dma_mapping_error(ss->dev, addr_xpad);
+		if (err) {
 			dev_err(ss->dev, "Fail to create DMA mapping of opad\n");
 			goto err_dma_xpad;
 		}