Sigma Designs Tango PCIe controller

Required properties:

- compatible: "sigma,smp8759-pcie"
- reg: address/size of PCI configuration space, address/size of register area
- bus-range: defined by size of PCI configuration space
- device_type: "pci"
- #size-cells: <2>
- #address-cells: <3>
- msi-controller
- ranges: translation from system to bus addresses
- interrupts: spec for misc interrupts, spec for MSI

Example:

	pcie@2e000 {
		compatible = "sigma,smp8759-pcie";
		reg = <0x50000000 0x400000>, <0x2e000 0x100>;
		bus-range = <0 3>;
		device_type = "pci";
		#size-cells = <2>;
		#address-cells = <3>;
		msi-controller;
		ranges = <0x02000000 0x0 0x00400000  0x50400000  0x0 0x3c00000>;
		interrupts =
			<54 IRQ_TYPE_LEVEL_HIGH>, /* misc interrupts */
			<55 IRQ_TYPE_LEVEL_HIGH>; /* MSI */
	};