pinctrl: imx8mn: Support building as module

Change configuration to "tristate", add module device table,
author, description and license to support building i.MX8MN
pinctrl driver as module.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Link: https://lore.kernel.org/r/1592979844-18833-5-git-send-email-Anson.Huang@nxp.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/freescale/Kconfig

@@ -131,7 +131,7 @@ config PINCTRL_IMX8MM
 	  Say Y here to enable the imx8mm pinctrl driver
 
 config PINCTRL_IMX8MN
-	bool "IMX8MN pinctrl driver"
+	tristate "IMX8MN pinctrl driver"
 	depends on ARCH_MXC
 	select PINCTRL_IMX
 	help

drivers/pinctrl/freescale/pinctrl-imx8mn.c

@@ -5,6 +5,7 @@
 
 #include <linux/err.h>
 #include <linux/init.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/platform_device.h>
@@ -326,6 +327,7 @@ static const struct of_device_id imx8mn_pinctrl_of_match[] = {
 	{ .compatible = "fsl,imx8mn-iomuxc", .data = &imx8mn_pinctrl_info, },
 	{ /* sentinel */ }
 };
+MODULE_DEVICE_TABLE(of, imx8mn_pinctrl_of_match);
 
 static int imx8mn_pinctrl_probe(struct platform_device *pdev)
 {
@@ -346,3 +348,7 @@ static int __init imx8mn_pinctrl_init(void)
 	return platform_driver_register(&imx8mn_pinctrl_driver);
 }
 arch_initcall(imx8mn_pinctrl_init);
+
+MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
+MODULE_DESCRIPTION("NXP i.MX8MN pinctrl driver");
+MODULE_LICENSE("GPL v2");