watchdog: eurotechwdt: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.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>

drivers/watchdog/eurotechwdt.c

@@ -290,7 +290,7 @@ static long eurwdt_ioctl(struct file *file,
 		eurwdt_timeout = time;
 		eurwdt_set_timeout(time);
 		spin_unlock(&eurwdt_lock);
-		/* Fall */
+		/* fall through */
 
 	case WDIOC_GETTIMEOUT:
 		return put_user(eurwdt_timeout, p);