* AppliedMicro X-Gene PCIe interface

Required properties:
- device_type: set to "pci"
- compatible: should contain "apm,xgene-pcie" to identify the core.
- reg: A list of physical base address and length for each set of controller
       registers. Must contain an entry for each entry in the reg-names
       property.
- reg-names: Must include the following entries:
  "csr": controller configuration registers.
  "cfg": pcie configuration space registers.
- #address-cells: set to <3>
- #size-cells: set to <2>
- ranges: ranges for the outbound memory, I/O regions.
- dma-ranges: ranges for the inbound memory regions.
- #interrupt-cells: set to <1>
- interrupt-map-mask and interrupt-map: standard PCI properties
	to define the mapping of the PCIe interface to interrupt
	numbers.
- clocks: from common clock binding: handle to pci clock.

Optional properties:
- status: Either "ok" or "disabled".
- dma-coherent: Present if dma operations are coherent

Example:

SoC specific DT Entry:

	pcie0: pcie@1f2b0000 {
		status = "disabled";
		device_type = "pci";
		compatible = "apm,xgene-storm-pcie", "apm,xgene-pcie";
		#interrupt-cells = <1>;
		#size-cells = <2>;
		#address-cells = <3>;
		reg = < 0x00 0x1f2b0000 0x0 0x00010000   /* Controller registers */
			0xe0 0xd0000000 0x0 0x00040000>; /* PCI config space */
		reg-names = "csr", "cfg";
		ranges = <0x01000000 0x00 0x00000000 0xe0 0x10000000 0x00 0x00010000   /* io */
			  0x02000000 0x00 0x80000000 0xe1 0x80000000 0x00 0x80000000>; /* mem */
		dma-ranges = <0x42000000 0x80 0x00000000 0x80 0x00000000 0x00 0x80000000
			      0x42000000 0x00 0x00000000 0x00 0x00000000 0x80 0x00000000>;
		interrupt-map-mask = <0x0 0x0 0x0 0x7>;
		interrupt-map = <0x0 0x0 0x0 0x1 &gic 0x0 0xc2 0x1
				 0x0 0x0 0x0 0x2 &gic 0x0 0xc3 0x1
				 0x0 0x0 0x0 0x3 &gic 0x0 0xc4 0x1
				 0x0 0x0 0x0 0x4 &gic 0x0 0xc5 0x1>;
		dma-coherent;
		clocks = <&pcie0clk 0>;
	};


Board specific DT Entry:
	&pcie0 {
		status = "ok";
	};
