rockchip: rk3288: Add pinctrl driver

Add a driver which supports pin multiplexing setup for the most commonly
used peripherals.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index 918a859..b8146df 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -105,6 +105,15 @@
 
 if PINCTRL || SPL_PINCTRL
 
+config ROCKCHIP_PINCTRL
+	bool "Rockchip pin control driver"
+	depends on DM
+	help
+	  Support pin multiplexing control on Rockchip SoCs. The driver is
+	  controlled by a device tree node which contains both the GPIO
+	  definitions and pin control functions for each available multiplex
+	  function.
+
 config PINCTRL_SANDBOX
 	bool "Sandbox pinctrl driver"
 	depends on SANDBOX