rockchip: serial: Add an of-platdata driver for rockchip

Add a driver that works with of-platdata. It sets up the platform data and
calls the standard ns16550 driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 0e38903..9ff7234 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -312,6 +312,15 @@
 	  be used. It can be a constant or a function to get clock, eg,
 	  get_serial_clock().
 
+config ROCKCHIP_SERIAL
+	bool "Rockchip on-chip UART support"
+	depends on DM_SERIAL && SPL_OF_PLATDATA
+	help
+	  Select this to enable a debug UART for Rockchip devices when using
+	  CONFIG_OF_PLATDATA (i.e. a compiled-in device tree replacemenmt).
+	  This uses the ns16550 driver, converting the platdata from of-platdata
+	  to the ns16550 format.
+
 config SANDBOX_SERIAL
 	bool "Sandbox UART support"
 	depends on SANDBOX