* Altera PCIe MSI controller

Required properties:
- compatible:	should contain "altr,msi-1.0"
- reg:		specifies the physical base address of the controller and
		the length of the memory mapped region.
- reg-names:	must include the following entries:
		"csr": CSR registers
		"vector_slave": vectors slave port region
- interrupts:	specifies the interrupt source of the parent interrupt
		controller. The format of the interrupt specifier depends on the
		parent interrupt controller.
- num-vectors:	number of vectors, range 1 to 32.
- msi-controller:	indicates that this is MSI controller node


Example
msi0: msi@0xFF200000 {
	compatible = "altr,msi-1.0";
	reg = <0xFF200000 0x00000010
		0xFF200010 0x00000080>;
	reg-names = "csr", "vector_slave";
	interrupt-parent = <&hps_0_arm_gic_0>;
	interrupts = <0 42 4>;
	msi-controller;
	num-vectors = <32>;
};
