RK3506

两个USB 2.0控制器usb20_otg0和usb20_otg1。
同时也有两个PHY，u2phy_otg0和u2phy_otg1。u2phy_otg0是OTG功能，u2phy_otg1是HOST功能。

&usb2phy {
	status = "okay";
};

&u2phy_otg0 {
	status = "okay";
};

&u2phy_otg1 {
	status = "okay";
};

&usb20_otg0 {
	status = "okay";
};

&usb20_otg1 {
	dr_mode = "host";
	status = "okay";
};