crypto: amlogic - Fix dma_map_sg error check

dma_map_sg return 0 on error.

Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Cc: linux-amlogic@lists.infradead.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/amlogic/amlogic-gxl-cipher.c

@@ -177,7 +177,7 @@ static int meson_cipher(struct skcipher_request *areq)
 	if (areq->src == areq->dst) {
 		nr_sgs = dma_map_sg(mc->dev, areq->src, sg_nents(areq->src),
 				    DMA_BIDIRECTIONAL);
-		if (nr_sgs < 0) {
+		if (!nr_sgs) {
 			dev_err(mc->dev, "Invalid SG count %d\n", nr_sgs);
 			err = -EINVAL;
 			goto theend;
@@ -186,14 +186,14 @@ static int meson_cipher(struct skcipher_request *areq)
 	} else {
 		nr_sgs = dma_map_sg(mc->dev, areq->src, sg_nents(areq->src),
 				    DMA_TO_DEVICE);
-		if (nr_sgs < 0 || nr_sgs > MAXDESC - 3) {
+		if (!nr_sgs || nr_sgs > MAXDESC - 3) {
 			dev_err(mc->dev, "Invalid SG count %d\n", nr_sgs);
 			err = -EINVAL;
 			goto theend;
 		}
 		nr_sgd = dma_map_sg(mc->dev, areq->dst, sg_nents(areq->dst),
 				    DMA_FROM_DEVICE);
-		if (nr_sgd < 0 || nr_sgd > MAXDESC - 3) {
+		if (!nr_sgd || nr_sgd > MAXDESC - 3) {
 			dev_err(mc->dev, "Invalid SG count %d\n", nr_sgd);
 			err = -EINVAL;
 			goto theend;