* Mobiveil AXI PCIe Root Port Bridge DT description

Mobiveil's GPEX 4.0 is a PCIe Gen4 root port bridge IP. This configurable IP
has up to 8 outbound and inbound windows for the address translation.

Required properties:
- #address-cells: Address representation for root ports, set to <3>
- #size-cells: Size representation for root ports, set to <2>
- #interrupt-cells: specifies the number of cells needed to encode an
	interrupt source. The value must be 1.
- compatible: Should contain "mbvl,gpex40-pcie"
- reg: Should contain PCIe registers location and length
	"config_axi_slave": PCIe controller registers
	"csr_axi_slave"	  : Bridge config registers
	"gpio_slave"	  : GPIO registers to control slot power
	"apb_csr"	  : MSI registers

- device_type: must be "pci"
- apio-wins : number of requested apio outbound windows
		default 2 outbound windows are configured -
		1. Config window
		2. Memory window
- ppio-wins : number of requested ppio inbound windows
		default 1 inbound memory window is configured.
- bus-range: PCI bus numbers covered
- interrupt-controller: identifies the node as an interrupt controller
- #interrupt-cells: specifies the number of cells needed to encode an
	interrupt source. The value must be 1.
- interrupt-parent : phandle to the interrupt controller that
		it is attached to, it should be set to gic to point to
		ARM's Generic Interrupt Controller node in system DT.
- interrupts: The interrupt line of the PCIe controller
		last cell of this field is set to 4 to
		denote it as IRQ_TYPE_LEVEL_HIGH type interrupt.
- interrupt-map-mask,
	interrupt-map: standard PCI properties to define the mapping of the
	PCI interface to interrupt numbers.
- ranges: ranges for the PCI memory regions (I/O space region is not
	supported by hardware)
	Please refer to the standard PCI bus binding document for a more
	detailed explanation


Example:
++++++++
	pcie0: pcie@a0000000 {
		#address-cells = <3>;
		#size-cells = <2>;
		compatible = "mbvl,gpex40-pcie";
		reg =	<0xa0000000 0x00001000>,
			<0xb0000000 0x00010000>,
			<0xff000000 0x00200000>,
			<0xb0010000 0x00001000>;
		reg-names =	"config_axi_slave",
				"csr_axi_slave",
				"gpio_slave",
				"apb_csr";
		device_type = "pci";
		apio-wins = <2>;
		ppio-wins = <1>;
		bus-range = <0x00000000 0x000000ff>;
		interrupt-controller;
		interrupt-parent = <&gic>;
		#interrupt-cells = <1>;
		interrupts = < 0 89 4 >;
		interrupt-map-mask = <0 0 0 7>;
		interrupt-map = <0 0 0 0 &pci_express 0>,
				<0 0 0 1 &pci_express 1>,
				<0 0 0 2 &pci_express 2>,
				<0 0 0 3 &pci_express 3>;
		ranges = < 0x83000000 0 0x00000000 0xa8000000 0 0x8000000>;

	};