pinctrl: ocelot: allow building as a module

Set PINCTRL_OCELOT config option as a tristate and add
MODULE_DEVICE_TABLE()/MODULE_LICENSE() to export appropriate
information. Moreover, switch from builtin_platform_driver()
to module_platform_driver().
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20220617103548.490092-1-clement.leger@bootlin.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/Kconfig

@@ -311,7 +311,7 @@ config PINCTRL_MICROCHIP_SGPIO
 	  LED controller.
 
 config PINCTRL_OCELOT
-	bool "Pinctrl driver for the Microsemi Ocelot and Jaguar2 SoCs"
+	tristate "Pinctrl driver for the Microsemi Ocelot and Jaguar2 SoCs"
 	depends on OF
 	depends on HAS_IOMEM
 	select GPIOLIB

drivers/pinctrl/pinctrl-ocelot.c

@@ -1889,6 +1889,7 @@ static const struct of_device_id ocelot_pinctrl_of_match[] = {
 	{ .compatible = "microchip,lan966x-pinctrl", .data = &lan966x_desc },
 	{},
 };
+MODULE_DEVICE_TABLE(of, ocelot_pinctrl_of_match);
 
 static struct regmap *ocelot_pinctrl_create_pincfg(struct platform_device *pdev)
 {
@@ -1984,4 +1985,5 @@ static struct platform_driver ocelot_pinctrl_driver = {
 	},
 	.probe = ocelot_pinctrl_probe,
 };
-builtin_platform_driver(ocelot_pinctrl_driver);
+module_platform_driver(ocelot_pinctrl_driver);
+MODULE_LICENSE("Dual MIT/GPL");