fec_mpc52xx: delete unneeded test before of_node_put

Of_node_put supports NULL as its argument, so the initial test is not
necessary.

Suggested by Uwe Kleine-König.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression e;
@@

-if (e)
   of_node_put(e);
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_mpc52xx.c

@@ -1015,7 +1015,6 @@ mpc52xx_fec_remove(struct platform_device *op)
 
 	unregister_netdev(ndev);
 
-	if (priv->phy_node)
 	of_node_put(priv->phy_node);
 	priv->phy_node = NULL;