rockchip: rk3128: add pinctrl driver

Add rk3128 pinctrl driver and grf/iomux structure definition.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index afca56d..7e8e4b0 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -168,6 +168,16 @@
 	  the GPIO definitions and pin control functions for each available
 	  multiplex function.
 
+config PINCTRL_ROCKCHIP_RK3128
+	bool "Rockchip rk3128 pin control driver"
+	depends on DM
+	help
+	  Support pin multiplexing control on Rockchip rk3128 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_ROCKCHIP_RK3188
 	bool "Rockchip rk3188 pin control driver"
 	depends on DM