watchdog: Fix rio watchdog probe function

After sucessfully registering the misc device the driver iounmaps the
hardware registers and kfree's the device data structure. Ouch !

This was introduced with commit e42311d75 (riowatchdog: Convert to
pure OF driver) and went unnoticed for more than a year :)

Return success instead of dropping into the error cleanup code path.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/watchdog/riowd.c

@@ -206,7 +206,7 @@ static int __devinit riowd_probe(struct of_device *op,
 
 	dev_set_drvdata(&op->dev, p);
 	riowd_device = p;
-	err = 0;
+	return 0;
 
 out_iounmap:
 	of_iounmap(&op->resource[0], p->regs, 2);