rtc: jz4740: Add support for the RTC in the jz4780 SoC

The RTC unit present in the JZ4780 works mostly the same as the one in
the JZ4740. The major difference is that register writes need to be
explicitly enabled, by writing a magic code (0xA55A) to a "write
enable" register before each access.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 4cbea34..1d0ae30 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1550,10 +1550,10 @@
 
 config RTC_DRV_JZ4740
 	tristate "Ingenic JZ4740 SoC"
-	depends on MACH_JZ4740 || COMPILE_TEST
+	depends on MACH_INGENIC || COMPILE_TEST
 	help
-	  If you say yes here you get support for the Ingenic JZ4740 SoC RTC
-	  controller.
+	  If you say yes here you get support for the Ingenic JZ47xx SoCs RTC
+	  controllers.
 
 	  This driver can also be buillt as a module. If so, the module
 	  will be called rtc-jz4740.