rtc: ds1347: simplify getting .driver_data

Get 'driver_data' from 'struct device' directly. Going via spi_device is an
unnecessary step.

Link: https://lore.kernel.org/r/20191007134724.15505-4-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-ds1347.c

@@ -43,13 +43,10 @@ static const struct regmap_access_table ds1347_access_table = {
 
 static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
 {
-	struct spi_device *spi = to_spi_device(dev);
-	struct regmap *map;
+	struct regmap *map = dev_get_drvdata(dev);
 	int err;
 	unsigned char buf[8];
 
-	map = spi_get_drvdata(spi);
-
 	err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
 	if (err)
 		return err;
@@ -67,12 +64,9 @@ static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
 
 static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
 {
-	struct spi_device *spi = to_spi_device(dev);
-	struct regmap *map;
+	struct regmap *map = dev_get_drvdata(dev);
 	unsigned char buf[8];
 
-	map = spi_get_drvdata(spi);
-
 	buf[0] = bin2bcd(dt->tm_sec);
 	buf[1] = bin2bcd(dt->tm_min);
 	buf[2] = (bin2bcd(dt->tm_hour) & 0x3F);