TI Keystone PCIe interface

Keystone PCI host Controller is based on Designware PCI h/w version 3.65.
It shares common functions with PCIe Designware core driver and inherit
common properties defined in
Documentation/devicetree/bindings/pci/designware-pci.txt

Please refer to Documentation/devicetree/bindings/pci/designware-pci.txt
for the details of Designware DT bindings.  Additional properties are
described here as well as properties that are not applicable.

Required Properties:-

compatibility: "ti,keystone-pcie"
reg:	index 1 is the base address and length of DW application registers.
	index 2 is the base address and length of PCI device ID register.

pcie_msi_intc : Interrupt controller device node for MSI IRQ chip
	interrupt-cells: should be set to 1
	interrupt-parent: Parent interrupt controller phandle
	interrupts: GIC interrupt lines connected to PCI MSI interrupt lines

 Example:
	pcie_msi_intc: msi-interrupt-controller {
			interrupt-controller;
			#interrupt-cells = <1>;
			interrupt-parent = <&gic>;
			interrupts = <GIC_SPI 30 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 31 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 32 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 33 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 34 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 35 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 36 IRQ_TYPE_EDGE_RISING>,
					<GIC_SPI 37 IRQ_TYPE_EDGE_RISING>;
	};

pcie_intc: Interrupt controller device node for Legacy IRQ chip
	interrupt-cells: should be set to 1
	interrupt-parent: Parent interrupt controller phandle
	interrupts: GIC interrupt lines connected to PCI Legacy interrupt lines

 Example:
	pcie_intc: legacy-interrupt-controller {
		interrupt-controller;
		#interrupt-cells = <1>;
		interrupt-parent = <&gic>;
		interrupts = <GIC_SPI 26 IRQ_TYPE_EDGE_RISING>,
			<GIC_SPI 27 IRQ_TYPE_EDGE_RISING>,
			<GIC_SPI 28 IRQ_TYPE_EDGE_RISING>,
			<GIC_SPI 29 IRQ_TYPE_EDGE_RISING>;
	};

Optional properties:-
	phys: phandle to Generic Keystone SerDes phy for PCI
	phy-names: name of the Generic Keystine SerDes phy for PCI
	  - If boot loader already does PCI link establishment, then phys and
	    phy-names shouldn't be present.
	interrupts: platform interrupt for error interrupts.

Designware DT Properties not applicable for Keystone PCI

1. pcie_bus clock-names not used.  Instead, a phandle to phys is used.

