* Freescale Layerscape SCFG PCIe MSI controller

Required properties:

- compatible: should be "fsl,<soc-name>-msi" to identify
	      Layerscape PCIe MSI controller block such as:
              "fsl,ls1021a-msi"
              "fsl,ls1043a-msi"
              "fsl,ls1046a-msi"
              "fsl,ls1043a-v1.1-msi"
              "fsl,ls1012a-msi"
- msi-controller: indicates that this is a PCIe MSI controller node
- reg: physical base address of the controller and length of memory mapped.
- interrupts: an interrupt to the parent interrupt controller.

Optional properties:
- interrupt-parent: the phandle to the parent interrupt controller.

This interrupt controller hardware is a second level interrupt controller that
is hooked to a parent interrupt controller: e.g: ARM GIC for ARM-based
platforms. If interrupt-parent is not provided, the default parent interrupt
controller will be used.
Each PCIe node needs to have property msi-parent that points to
MSI controller node

Examples:

	msi1: msi-controller@1571000 {
		compatible = "fsl,ls1043a-msi";
		reg = <0x0 0x1571000 0x0 0x8>,
		msi-controller;
		interrupts = <0 116 0x4>;
	};
