drivers/rtc/rtc-pcf50633.c: fix use after free in pcf50633_rtc_probe()

"rtc" is freed and then dereferenced on the next line.  This patch fixes
that.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Acked-by: NAlessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-pcf50633.c

@@ -292,8 +292,9 @@ static int __devinit pcf50633_rtc_probe(struct platform_device *pdev)
 				&pcf50633_rtc_ops, THIS_MODULE);
 
 	if (IS_ERR(rtc->rtc_dev)) {
+		int ret =  PTR_ERR(rtc->rtc_dev);
 		kfree(rtc);
-		return PTR_ERR(rtc->rtc_dev);
+		return ret;
 	}
 
 	pcf50633_register_irq(rtc->pcf, PCF50633_IRQ_ALARM,