watchdog: gpio: change order for setting default timeout

watchdog_init_timeout() will preserve wdd->timeout value if
no parameter nor timeout-secs dt property is set.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>