arm64: dts: imx8mq-nitrogen: add USB OTG support

Add the description for the USB OTG port.
The OTG port uses a dedicated regulator for vbus.
Signed-off-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-nitrogen.dts

@@ -34,6 +34,17 @@ power {
 		};
 	};
 
+	reg_usb_otg_vbus: regulator-usb-otg-vbus {
+		compatible = "regulator-fixed";
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_reg_usbotg_vbus>;
+		regulator-name = "usb_otg_vbus";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		gpio = <&gpio1 12 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+	};
+
 	reg_vref_0v9: regulator-vref-0v9 {
 		compatible = "regulator-fixed";
 		regulator-name = "vref-0v9";
@@ -190,6 +201,18 @@ &uart2 {
 	status = "okay";
 };
 
+&usb_dwc3_0 {
+	dr_mode = "otg";
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usb3_0>;
+	status = "okay";
+};
+
+&usb3_phy0 {
+	vbus-supply = <&reg_usb_otg_vbus>;
+	status = "okay";
+};
+
 &usdhc1 {
 	assigned-clocks = <&clk IMX8MQ_CLK_USDHC1>;
 	assigned-clock-rates = <400000000>;
@@ -339,6 +362,12 @@ MX8MQ_IOMUXC_SD2_WP_GPIO2_IO20		0x16
 		>;
 	};
 
+	pinctrl_reg_usbotg_vbus: reg-usbotg-vbusgrp {
+		fsl,pins = <
+			MX8MQ_IOMUXC_GPIO1_IO12_GPIO1_IO12	0x16
+		>;
+	};
+
 	pinctrl_uart1: uart1grp {
 		fsl,pins = <
 			MX8MQ_IOMUXC_UART1_RXD_UART1_DCE_RX		0x45
@@ -353,6 +382,12 @@ MX8MQ_IOMUXC_UART2_TXD_UART2_DCE_TX		0x45
 		>;
 	};
 
+	pinctrl_usb3_0: usb3-0grp {
+		fsl,pins = <
+			MX8MQ_IOMUXC_GPIO1_IO13_USB1_OTG_OC		0x16
+		>;
+	};
+
 	pinctrl_usdhc1: usdhc1grp {
 		fsl,pins = <
 			MX8MQ_IOMUXC_SD1_CLK_USDHC1_CLK			0x83