reset: meson: make it possible to build as a module

In order to reduce the kernel Image size on multi-platform distributions,
make it possible to build the reset controller driver as a module.

This partially reverts commit 8290924e ("reset: meson: make it
explicitly non-modular").
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/Kconfig

@@ -95,7 +95,8 @@ config RESET_LPC18XX
 	  This enables the reset controller driver for NXP LPC18xx/43xx SoCs.
 
 config RESET_MESON
-	bool "Meson Reset Driver" if COMPILE_TEST
+	tristate "Meson Reset Driver"
+	depends on ARCH_MESON || COMPILE_TEST
 	default ARCH_MESON
 	help
 	  This enables the reset driver for Amlogic Meson SoCs.

drivers/reset/reset-meson.c

@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
@@ -104,6 +105,7 @@ static const struct of_device_id meson_reset_dt_ids[] = {
 	 { .compatible = "amlogic,meson-a1-reset",   .data = &meson_a1_param},
 	 { /* sentinel */ },
 };
+MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
 
 static int meson_reset_probe(struct platform_device *pdev)
 {
@@ -142,4 +144,8 @@ static struct platform_driver meson_reset_driver = {
 		.of_match_table	= meson_reset_dt_ids,
 	},
 };
-builtin_platform_driver(meson_reset_driver);
+module_platform_driver(meson_reset_driver);
+
+MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("Dual BSD/GPL");