watchdog: imx2_wdt: Fix set_timeout for big timeout values

The documentated behavior is: if max_hw_heartbeat_ms is implemented, the
minimum of the set_timeout argument and max_hw_heartbeat_ms should be used.
This patch implements this behavior.
Previously only the first 7bits were used and the input argument was
returned.

Signed-off-by: Georg Hofmann <georg@hofmannsweb.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@linux-watchdog.org>

drivers/watchdog/imx2_wdt.c

@@ -178,8 +178,10 @@ static void __imx2_wdt_set_timeout(struct watchdog_device *wdog,
 static int imx2_wdt_set_timeout(struct watchdog_device *wdog,
 				unsigned int new_timeout)
 {
-	__imx2_wdt_set_timeout(wdog, new_timeout);
+	unsigned int actual;
 
+	actual = min(new_timeout, wdog->max_hw_heartbeat_ms * 1000);
+	__imx2_wdt_set_timeout(wdog, actual);
 	wdog->timeout = new_timeout;
 	return 0;
 }