powerpc/powermac: of_node_put() is not needed after iterator

for_each_node_by_name() iterators only exit normally when the loop
cursor is NULL, So there is no need to call of_node_put().
Signed-off-by: Nzhong jiang <zhongjiang@huawei.com>
Reviewed-by: NTyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powermac/feature.c

@@ -2889,10 +2889,8 @@ set_initial_features(void)
 	/* On all machines, switch modem & serial ports off */
 	for_each_node_by_name(np, "ch-a")
 		initial_serial_shutdown(np);
-	of_node_put(np);
 	for_each_node_by_name(np, "ch-b")
 		initial_serial_shutdown(np);
-	of_node_put(np);
 }
 
 void __init