rtc: mrst: fix error code in probe()

We should be returning "retval".  The "mrst_rtc.rtc" variable is a valid
pointer.

Fixes: 32b41f93dcaf ("rtc: mrst: switch to devm functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-mrst.c

@@ -367,10 +367,8 @@ static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem,
 	}
 
 	retval = rtc_register_device(mrst_rtc.rtc);
-	if (retval) {
-		retval = PTR_ERR(mrst_rtc.rtc);
+	if (retval)
 		goto cleanup0;
-	}
 
 	dev_dbg(dev, "initialised\n");
 	return 0;