rtc: ds1374: wdt: Fix stop/start ioctl always returning -EINVAL

The WDIOC_SETOPTIONS case in the watchdog ioctl would alwayss falls
through to the -EINVAL case. This is wrong since thew watchdog does
actually get stopped or started correctly.

Fixes: 920f91e5 ("drivers/rtc/rtc-ds1374.c: add watchdog support")
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-ds1374.c

@@ -546,14 +546,15 @@ static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
 		if (options & WDIOS_DISABLECARD) {
 			pr_info("disable watchdog\n");
 			ds1374_wdt_disable();
+			return 0;
 		}
 
 		if (options & WDIOS_ENABLECARD) {
 			pr_info("enable watchdog\n");
 			ds1374_wdt_settimeout(wdt_margin);
 			ds1374_wdt_ping();
+			return 0;
 		}
-
 		return -EINVAL;
 	}
 	return -ENOTTY;