rtc: add Microcrystal RV-8803 driver

Signed-off-by: Michael Walle <michael@walle.cc>
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 1724602..915adb8 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -46,6 +46,7 @@
 obj-$(CONFIG_RTC_PT7C4338) += pt7c4338.o
 obj-$(CONFIG_RTC_RS5C372A) += rs5c372.o
 obj-$(CONFIG_RTC_RV3029) += rv3029.o
+obj-$(CONFIG_RTC_RV8803) += rv8803.o
 obj-$(CONFIG_RTC_RX8025) += rx8025.o
 obj-$(CONFIG_RTC_RX8010SJ) += rx8010sj.o
 obj-$(CONFIG_RTC_S3C24X0) += s3c24x0_rtc.o