i2c: mpc: 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: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-mpc.c

@@ -341,8 +341,7 @@ static u32 mpc_i2c_get_sec_cfg_8xxx(void)
 			iounmap(reg);
 		}
 	}
-	if (node)
-		of_node_put(node);
+	of_node_put(node);
 
 	return val;
 }