watchdog: meson: 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: NMarcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

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

@@ -9,9 +9,13 @@ Required properties:
 	"amlogic,meson8m2-wdt" and "amlogic,meson8b-wdt" on Meson8m2 SoCs
 - reg : Specifies base physical address and size of the registers.
 
+Optional properties:
+- timeout-sec: contains the watchdog timeout in seconds.
+
 Example:
 
 wdt: watchdog@c1109900 {
 	compatible = "amlogic,meson6-wdt";
 	reg = <0xc1109900 0x8>;
+	timeout-sec = <10>;
 };

drivers/watchdog/meson_wdt.c

@@ -36,7 +36,7 @@
 #define MESON_SEC_TO_TC(s, c)	((s) * (c))
 
 static bool nowayout = WATCHDOG_NOWAYOUT;
-static unsigned int timeout = MESON_WDT_TIMEOUT;
+static unsigned int timeout;
 
 struct meson_wdt_data {
 	unsigned int enable;