MSM PCI express endpoint

Required properties:
  - compatible: should be "qcom,pcie-ep".
  - reg: should contain PCIe register maps.
  - reg-names: indicates various resources passed to driver by name.
		Should be "msi", "dm_core", "elbi", "parf", "phy", "mmio".
		These correspond to different modules within the PCIe domain.
  - #address-cells: Should provide a value of 0.
  - interrupt-parent: Should be the PCIe device node itself here.
  - interrupts: Should be in the format <0 1 2> and it is an index to the
		interrupt-map that contains PCIe related interrupts.
  - #interrupt-cells: Should provide a value of 1.
  - #interrupt-map-mask: should provide a value of 0xffffffff.
  - interrupt-map:  Must create mapping for the number of interrupts
		    that are defined in above interrupts property.
		    For PCIe device node, it should define 6 mappings for
		    the corresponding PCIe interrupts supporting the
		    specification.
  - interrupt-names: indicates interrupts passed to driver by name.
		     Should be "int_pm_turnoff", "int_dstate_change",
				"int_l1sub_timeout", "int_link_up",
				"int_link_down", "int_bridge_flush_n".
  - perst-gpio: PERST GPIO specified by PCIe spec.
  - wake-gpio: WAKE GPIO specified by PCIe spec.
  - clkreq-gpio: CLKREQ GPIO specified by PCIe spec.
  - <supply-name>-supply: phandle to the regulator device tree node.
    Refer to the schematics for the corresponding voltage regulators.
    vreg-1.8-supply: phandle to the analog supply for the PCIe controller.
    vreg-0.9-supply: phandle to the analog supply for the PCIe controller.

Optional Properties:
  - qcom,<supply-name>-voltage-level: specifies voltage levels for supply.
    Should be specified in pairs (max, min, optimal), units uV.
  - clock-names: list of names of clock inputs.
		     Should be "pcie_0_pipe_clk",
				"pcie_0_aux_clk", "pcie_0_cfg_ahb_clk",
				"pcie_0_mstr_axi_clk", "pcie_0_slv_axi_clk",
				"pcie_0_ldo";
  - max-clock-frequency-hz: list of the maximum operating frequencies stored
				in the same order of clock names;
  - qcom,pcie-phy-ver: version of PCIe PHY.
  - qcom,pcie-link-speed: generation of PCIe link speed. The value could be
    1, 2 or 3.
  - qcom,pcie-active-config: boolean type; active configuration of PCIe
    addressing.
  - qcom,pcie-aggregated-irq: boolean type; interrupts are aggregated.
  - mdm2apstatus-gpio: GPIO used by PCIe endpoint side to notify the host side.
  - Refer to "Documentation/devicetree/bindings/arm/msm/msm_bus.txt" for
    below optional properties:
	- qcom,msm-bus,name
	- qcom,msm-bus,num-cases
	- qcom,msm-bus,num-paths
	- qcom,msm-bus,vectors-KBps

Example:

	pcie_ep: qcom,pcie@bfffd000 {
		compatible = "qcom,pcie-ep";

		reg = <0xbfffd000 0x1000>,
			<0xbfffe000 0x1000>,
			<0xbffff000 0x1000>,
			<0xfc520000 0x2000>,
			<0xfc526000 0x1000>,
			<0xfc527000 0x1000>;
		reg-names = "msi", "dm_core", "elbi", "parf", "phy", "mmio";

		#address-cells = <0>;
		interrupt-parent = <&pcie_ep>;
		interrupts = <0 1 2 3 4 5>;
		#interrupt-cells = <1>;
		interrupt-map-mask = <0xffffffff>;
		interrupt-map = <0 &intc 0 44 0
				1 &intc 0 46 0
				2 &intc 0 47 0
				3 &intc 0 50 0
				4 &intc 0 51 0
				5 &intc 0 52 0>;
		interrupt-names = "int_pm_turnoff", "int_dstate_change",
				"int_l1sub_timeout", "int_link_up",
				"int_link_down", "int_bridge_flush_n";

		perst-gpio = <&msmgpio 65 0>;
		wake-gpio = <&msmgpio 61 0>;
		clkreq-gpio = <&msmgpio 64 0>;
		mdm2apstatus-gpio = <&tlmm_pinmux 16 0>;

		gdsc-vdd-supply = <&gdsc_pcie_0>;
		vreg-1.8-supply = <&pmd9635_l8>;
		vreg-0.9-supply = <&pmd9635_l4>;

		qcom,vreg-1.8-voltage-level = <1800000 1800000 1000>;
		qcom,vreg-0.9-voltage-level = <950000 950000 24000>;

		clock-names = "pcie_0_pipe_clk",
				"pcie_0_aux_clk", "pcie_0_cfg_ahb_clk",
				"pcie_0_mstr_axi_clk", "pcie_0_slv_axi_clk",
				"pcie_0_ldo";
		max-clock-frequency-hz = <62500000>, <1000000>,
						<0>, <0>, <0>, <0>;

		qcom,msm-bus,name = "pcie-ep";
		qcom,msm-bus,num-cases = <2>;
		qcom,msm-bus,num-paths = <1>;
		qcom,msm-bus,vectors-KBps =
				<45 512 0 0>,
				<45 512 500 800>;

		qcom,pcie-link-speed = <1>;
		qcom,pcie-active-config;
		qcom,pcie-aggregated-irq;
	};