pci: add Amlogic Meson Designware PCIe controller

Add support for the DW PCIe controller found in the Amlogic Meson AXG and
G12 (G12A, G12B, SM1) SoCs.
This uses the common DW PCIe helpers introducted previously.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index cacfc4b..cdcdd8f 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -276,6 +276,14 @@
 	  Say Y here if you want to enable Gen2 PCIe controller,
 	  which could be found on MT7623 SoC family.
 
+config PCIE_DW_MESON
+	bool "Amlogic Meson DesignWare based PCIe controller"
+	depends on ARCH_MESON
+	select PCIE_DW_COMMON
+	help
+	  Say Y here if you want to enable DW PCIe controller support on
+	  Amlogic SoCs.
+
 config PCIE_ROCKCHIP
 	bool "Enable Rockchip PCIe driver"
 	depends on ARCH_ROCKCHIP