net: ti: cpmac: Use the correct function to free some resources.

In 'cpmac_open', 'dma_alloc_coherent' has been used to allocate some
resources, so we need to free them using 'dma_free_coherent' instead
of 'kfree'.

Also, we don't need to free these resources if the allocation has failed.
So I have slighly modified the goto label in this case.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/cpmac.c

@@ -1006,8 +1006,10 @@ fail_desc:
 			kfree_skb(priv->rx_head[i].skb);
 		}
 	}
+	dma_free_coherent(&dev->dev, sizeof(struct cpmac_desc) * size,
+			  priv->desc_ring, priv->dma_ring);
+
 fail_alloc:
-	kfree(priv->desc_ring);
 	iounmap(priv->regs);
 
 fail_remap: