PCI: meson: Build as module by default

Enable pci-meson to build as a module whenever ARCH_MESON is enabled.

Link: https://lore.kernel.org/r/20200918181251.32423-1-khilman@baylibre.com
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Cc: Yue Wang <yue.wang@amlogic.com>

drivers/pci/controller/dwc/Kconfig

@@ -237,8 +237,9 @@ config PCIE_HISI_STB
 	  Say Y here if you want PCIe controller support on HiSilicon STB SoCs
 
 config PCI_MESON
-	bool "MESON PCIe controller"
+	tristate "MESON PCIe controller"
 	depends on PCI_MSI_IRQ_DOMAIN
+	default m if ARCH_MESON
 	select PCIE_DW_HOST
 	help
 	  Say Y here if you want to enable PCI controller support on Amlogic

drivers/pci/controller/dwc/pci-meson.c

@@ -17,6 +17,7 @@
 #include <linux/resource.h>
 #include <linux/types.h>
 #include <linux/phy/phy.h>
+#include <linux/module.h>
 
 #include "pcie-designware.h"
 
@@ -589,6 +590,7 @@ static const struct of_device_id meson_pcie_of_match[] = {
 	},
 	{},
 };
+MODULE_DEVICE_TABLE(of, meson_pcie_of_match);
 
 static struct platform_driver meson_pcie_driver = {
 	.probe = meson_pcie_probe,
@@ -598,4 +600,8 @@ static struct platform_driver meson_pcie_driver = {
 	},
 };
 
-builtin_platform_driver(meson_pcie_driver);
+module_platform_driver(meson_pcie_driver);
+
+MODULE_AUTHOR("Yue Wang <yue.wang@amlogic.com>");
+MODULE_DESCRIPTION("Amlogic PCIe Controller driver");
+MODULE_LICENSE("GPL v2");