rtc: rtc-m41t94: use spi_set_drvdata()

Use the wrapper functions for getting and setting the driver data using
spi_device instead of using dev_{get|set}_drvdata with &spi->dev, so we
can directly pass a struct spi_device.
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>

drivers/rtc/rtc-m41t94.c

@@ -129,7 +129,7 @@ static int m41t94_probe(struct spi_device *spi)
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
 
-	dev_set_drvdata(&spi->dev, rtc);
+	spi_set_drvdata(spi, rtc);
 
 	return 0;
 }