net: ethernet: micrel: fix an error code

The dma_mapping_error() function returns true or false.  We should
return -ENOMEM if it there is a dma mapping error.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/micrel/ks8842.c

@@ -952,9 +952,8 @@ static int ks8842_alloc_dma_bufs(struct net_device *netdev)
 
 	sg_dma_address(&tx_ctl->sg) = dma_map_single(adapter->dev,
 		tx_ctl->buf, DMA_BUFFER_SIZE, DMA_TO_DEVICE);
-	err = dma_mapping_error(adapter->dev,
-		sg_dma_address(&tx_ctl->sg));
-	if (err) {
+	if (dma_mapping_error(adapter->dev, sg_dma_address(&tx_ctl->sg))) {
+		err = -ENOMEM;
 		sg_dma_address(&tx_ctl->sg) = 0;
 		goto err;
 	}