rtc: add new lp8788 rtc driver

TI LP8788 PMU supports regulators, battery charger, RTC, ADC, backlight
driver and current sinks.  This patch enables LP8788 rtc module.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Cc: "devendra.aaru" <devendra.aaru@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/Kconfig

@@ -204,6 +204,12 @@ config RTC_DRV_DS3232
 	  This driver can also be built as a module.  If so, the module
 	  will be called rtc-ds3232.
 
+config RTC_DRV_LP8788
+	tristate "TI LP8788 RTC driver"
+	depends on MFD_LP8788
+	help
+	  Say Y to enable support for the LP8788 RTC/ALARM driver.
+
 config RTC_DRV_MAX6900
 	tristate "Maxim MAX6900"
 	help