rtc: ds1347: changed raw spi calls to register map calls

This patch changes calls of spi read write calls to register map
read and write calls in rtc ds1347

Signed-off-by: Raghavendra Chandra Ganiga <ravi23ganiga@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 531343a..4f6bda8 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -665,6 +665,7 @@
 	  will be called rtc-ds1343.
 
 config RTC_DRV_DS1347
+	select REGMAP_SPI
 	tristate "Dallas/Maxim DS1347"
 	help
 	  If you say yes here you get support for the