pinctrl: Add pinctrl driver for i.MX8

Add pinctrl driver for i.MX8. The pads configuration is controlled
by SCU, so need to ask SCU to configure pads through scfw API.
Add pinctrl-scu to invoke sc_pad_set to configure pads.
Add a new flag IMX8_USE_SCU to differentiate i.MX8 from other platforms
which could directly configure pads from Acore side.
Add CONFIG_PINCTRL_IMX8 as the built gate.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/drivers/pinctrl/nxp/Kconfig b/drivers/pinctrl/nxp/Kconfig
index b668359..799d1d2 100644
--- a/drivers/pinctrl/nxp/Kconfig
+++ b/drivers/pinctrl/nxp/Kconfig
@@ -1,6 +1,9 @@
 config PINCTRL_IMX
 	bool
 
+config PINCTRL_IMX_SCU
+	bool
+
 config PINCTRL_IMX5
 	bool "IMX5 pinctrl driver"
 	depends on ARCH_MX5 && PINCTRL_FULL
@@ -56,3 +59,18 @@
 	  is different from the linux one, this is a simple implementation,
 	  only parses the 'fsl,pins' property and configure related
 	  registers.
+
+config PINCTRL_IMX8
+	bool "IMX8 pinctrl driver"
+	depends on ARCH_IMX8 && PINCTRL_FULL
+	select DEVRES
+	select PINCTRL_IMX
+	select PINCTRL_IMX_SCU
+	help
+	  Say Y here to enable the imx8 pinctrl driver
+
+	  This provides a simple pinctrl driver for i.MX8 SoC familiy.
+	  This feature depends on device tree configuration. This driver
+	  is different from the linux one, this is a simple implementation,
+	  only parses the 'fsl,pins' property and configures related
+	  registers.