[WATCHDOG] fix mtx1_wdt compilation failure

Using spin_lock_irqsave with a local variable called flags without
declaring is a bad idea, fix this by declaring it.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/mtx-1_wdt.c

@@ -98,6 +98,8 @@ static void mtx1_wdt_reset(void)
 
 static void mtx1_wdt_start(void)
 {
+	unsigned long flags;
+
 	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 	if (!mtx1_wdt_device.queue) {
 		mtx1_wdt_device.queue = 1;
@@ -110,6 +112,8 @@ static void mtx1_wdt_start(void)
 
 static int mtx1_wdt_stop(void)
 {
+	unsigned long flags;
+
 	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
 	if (mtx1_wdt_device.queue) {
 		mtx1_wdt_device.queue = 0;