MediaTek musb DRD/OTG controller
-------------------------------------------

Required properties:
 - compatible      : should be one of:
                     "mediatek,mt2701-musb"
                     ...
                     followed by "mediatek,mtk-musb"
 - reg             : specifies physical base address and size of
                     the registers
 - interrupts      : interrupt used by musb controller
 - interrupt-names : must be "mc"
 - phys            : PHY specifier for the OTG phy
 - dr_mode         : should be one of "host", "peripheral" or "otg",
                     refer to usb/generic.txt
 - clocks          : a list of phandle + clock-specifier pairs, one for
                     each entry in clock-names
 - clock-names     : must contain "main", "mcu", "univpll"
                     for clocks of controller

Optional properties:
 - power-domains   : a phandle to USB power domain node to control USB's
                     MTCMOS

Required child nodes:
 usb connector node as defined in bindings/connector/usb-connector.txt
Optional properties:
 - id-gpios        : input GPIO for USB ID pin.
 - vbus-gpios      : input GPIO for USB VBUS pin.
 - vbus-supply     : reference to the VBUS regulator, needed when supports
                     dual-role mode
 - usb-role-switch : use USB Role Switch to support dual-role switch, see
                     usb/generic.txt.

Example:

usb2: usb@11200000 {
	compatible = "mediatek,mt2701-musb",
		     "mediatek,mtk-musb";
	reg = <0 0x11200000 0 0x1000>;
	interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_LOW>;
	interrupt-names = "mc";
	phys = <&u2port2 PHY_TYPE_USB2>;
	dr_mode = "otg";
	clocks = <&pericfg CLK_PERI_USB0>,
		 <&pericfg CLK_PERI_USB0_MCU>,
		 <&pericfg CLK_PERI_USB_SLV>;
	clock-names = "main","mcu","univpll";
	power-domains = <&scpsys MT2701_POWER_DOMAIN_IFR_MSC>;
	usb-role-switch;
	connector{
		compatible = "gpio-usb-b-connector", "usb-b-connector";
		type = "micro";
		id-gpios = <&pio 44 GPIO_ACTIVE_HIGH>;
		vbus-supply = <&usb_vbus>;
	};
};