ARM: mvebu: fix a leaked reference by adding missing of_node_put

The call to of_get_next_child returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

Detected by coccinelle with the following warnings:
./arch/arm/mach-mvebu/pm-board.c:135:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 88, but without a corresponding object release within this functio
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@bootlin.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

arch/arm/mach-mvebu/pm-board.c

@@ -79,7 +79,7 @@ static void mvebu_armada_pm_enter(void __iomem *sdram_reg, u32 srcmd)
 static int __init mvebu_armada_pm_init(void)
 {
 	struct device_node *np;
-	struct device_node *gpio_ctrl_np;
+	struct device_node *gpio_ctrl_np = NULL;
 	int ret = 0, i;
 
 	if (!of_machine_is_compatible("marvell,axp-gp"))
@@ -126,18 +126,23 @@ static int __init mvebu_armada_pm_init(void)
 			goto out;
 		}
 
+		if (gpio_ctrl_np)
+			of_node_put(gpio_ctrl_np);
 		gpio_ctrl_np = args.np;
 		pic_raw_gpios[i] = args.args[0];
 	}
 
 	gpio_ctrl = of_iomap(gpio_ctrl_np, 0);
-	if (!gpio_ctrl)
-		return -ENOMEM;
+	if (!gpio_ctrl) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	mvebu_pm_suspend_init(mvebu_armada_pm_enter);
 
 out:
 	of_node_put(np);
+	of_node_put(gpio_ctrl_np);
 	return ret;
 }