* AppliedMicro X-Gene v1 PCIe MSI controller

Required properties:

- compatible: should be "apm,xgene1-msi" to identify
	      X-Gene v1 PCIe MSI controller block.
- msi-controller: indicates that this is X-Gene v1 PCIe MSI controller node
- reg: physical base address (0x79000000) and length (0x900000) for controller
       registers. These registers include the MSI termination address and data
       registers as well as the MSI interrupt status registers.
- reg-names: not required
- interrupts: A list of 16 interrupt outputs of the controller, starting from
	      interrupt number 0x10 to 0x1f.
- interrupt-names: not required

Each PCIe node needs to have property msi-parent that points to msi controller node

Examples:

SoC DTSI:

	+ MSI node:
	msi@79000000 {
		compatible = "apm,xgene1-msi";
		msi-controller;
		reg = <0x00 0x79000000 0x0 0x900000>;
		interrupts = 	<0x0 0x10 0x4>
				<0x0 0x11 0x4>
				<0x0 0x12 0x4>
				<0x0 0x13 0x4>
				<0x0 0x14 0x4>
				<0x0 0x15 0x4>
				<0x0 0x16 0x4>
				<0x0 0x17 0x4>
				<0x0 0x18 0x4>
				<0x0 0x19 0x4>
				<0x0 0x1a 0x4>
				<0x0 0x1b 0x4>
				<0x0 0x1c 0x4>
				<0x0 0x1d 0x4>
				<0x0 0x1e 0x4>
				<0x0 0x1f 0x4>;
	};

	+ PCIe controller node with msi-parent property pointing to MSI node:
	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>;
		msi-parent= <&msi>;
	};