HiSilicon STB xHCI

The device node for HiSilicon STB xHCI host controller

Required properties:
 - compatible: should be "hisilicon,hi3798cv200-xhci"
 - reg: specifies physical base address and size of the registers
 - interrupts : interrupt used by the controller
 - clocks: a list of phandle + clock-specifier pairs, one for each
	entry in clock-names
 - clock-names: must contain
	"bus": for bus clock
	"utmi": for utmi clock
	"pipe": for pipe clock
	"suspend": for suspend clock
 - resets: a list of phandle and reset specifier pairs as listed in
	reset-names property.
 - reset-names: must contain
	"soft": for soft reset
 - phys: a list of phandle + phy specifier pairs
 - phy-names: must contain at least one of following:
	"inno": for inno phy
	"combo": for combo phy

Optional properties:
  - usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
  - usb3-lpm-capable: determines if platform is USB3 LPM capable
  - imod-interval-ns: default interrupt moderation interval is 40000ns

Example:

xhci0: xchi@f98a0000 {
	compatible = "hisilicon,hi3798cv200-xhci";
	reg = <0xf98a0000 0x10000>;
	interrupts = <GIC_SPI 69 IRQ_TYPE_LEVEL_HIGH>;
	clocks = <&crg HISTB_USB3_BUS_CLK>,
		 <&crg HISTB_USB3_UTMI_CLK>,
		 <&crg HISTB_USB3_PIPE_CLK>,
		 <&crg HISTB_USB3_SUSPEND_CLK>;
	clock-names = "bus", "utmi", "pipe", "suspend";
	resets = <&crg 0xb0 12>;
	reset-names = "soft";
	phys = <&usb2_phy1_port1 0>, <&combphy0 PHY_TYPE_USB3>;
	phy-names = "inno", "combo";
};