powerpc/numa: Use of_get_next_parent to simplify code

of_get_next_parent can be used to simplify the while() loop and
avoid the need of a temp variable.
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/numa.c

@@ -276,7 +276,6 @@ static int of_node_to_nid_single(struct device_node *device)
 /* Walk the device tree upwards, looking for an associativity id */
 int of_node_to_nid(struct device_node *device)
 {
-	struct device_node *tmp;
 	int nid = -1;
 
 	of_node_get(device);
@@ -285,9 +284,7 @@ int of_node_to_nid(struct device_node *device)
 		if (nid != -1)
 			break;
 
-	        tmp = device;
-		device = of_get_parent(tmp);
-		of_node_put(tmp);
+		device = of_get_next_parent(device);
 	}
 	of_node_put(device);