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>
 
        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;
        }