HiSilicon PCIe host bridge DT description

HiSilicon PCIe host controller is based on Designware PCI core.
It shares common functions with PCIe Designware core driver and inherits
common properties defined in
Documentation/devicetree/bindings/pci/designware-pci.txt.

Additional properties are described here:

Required properties:
- compatible: Should contain "hisilicon,hip05-pcie".
- reg: Should contain rc_dbi, config registers location and length.
- reg-names: Must include the following entries:
  "rc_dbi": controller configuration registers;
  "config": PCIe configuration space registers.
- msi-parent: Should be its_pcie which is an ITS receiving MSI interrupts.
- port-id: Should be 0, 1, 2 or 3.

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

Example:
	pcie@0xb0080000 {
		compatible = "hisilicon,hip05-pcie", "snps,dw-pcie";
		reg = <0 0xb0080000 0 0x10000>, <0x220 0x00000000 0 0x2000>;
		reg-names = "rc_dbi", "config";
		bus-range = <0  15>;
		msi-parent = <&its_pcie>;
		#address-cells = <3>;
		#size-cells = <2>;
		device_type = "pci";
		dma-coherent;
		ranges = <0x82000000 0 0x00000000 0x220 0x00000000 0 0x10000000>;
		num-lanes = <8>;
		port-id = <1>;
		#interrupts-cells = <1>;
		interrupts-map-mask = <0xf800 0 0 7>;
		interrupts-map = <0x0 0 0 1 &mbigen_pcie 1 10
				  0x0 0 0 2 &mbigen_pcie 2 11
				  0x0 0 0 3 &mbigen_pcie 3 12
				  0x0 0 0 4 &mbigen_pcie 4 13>;
		status = "ok";
	};
