The driver core clears the driver data to NULL after device_release or
on probe failure, since commit 
0998d063100 ("device-core: Ensure drvdata
= NULL when no driver is bound").  Thus, it is not needed to manually
clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 
 err_unregister_rtc:
        rtc_device_unregister(rtc->rtc);
 err_iounmap:
-       platform_set_drvdata(pdev, NULL);
        iounmap(rtc->base);
 err_release_mem_region:
        release_mem_region(rtc->mem->start, resource_size(rtc->mem));
 
        kfree(rtc);
 
-       platform_set_drvdata(pdev, NULL);
-
        return 0;
 }