watchdog: mtk: allow setting timeout in devicetree

watchdog_init_timeout() will allways pick timeout_param since it
defaults to a valid timeout.

By following best practice described in
Documentation/watchdog/watchdog-kernel-api.txt, it also
let us to set timout-sec property in devicetree.
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Documentation/devicetree/bindings/watchdog/mtk-wdt.txt

@@ -11,9 +11,13 @@ Required properties:
 
 - reg : Specifies base physical address and size of the registers.
 
+Optional properties:
+- timeout-sec: contains the watchdog timeout in seconds.
+
 Example:
 
 wdt: watchdog@10000000 {
 	compatible = "mediatek,mt6589-wdt";
 	reg = <0x10000000 0x18>;
+	timeout-sec = <10>;
 };

drivers/watchdog/mtk_wdt.c

@@ -57,7 +57,7 @@
 #define DRV_VERSION		"1.0"
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
-static unsigned int timeout = WDT_MAX_TIMEOUT;
+static unsigned int timeout;
 
 struct mtk_wdt_dev {
 	struct watchdog_device wdt_dev;