arm64: dts: imx8mm-nitrogen-r2: add USB support

Add description of USB.
usbotg2 seems to not working on all boards (including ones
from variscite).
Signed-off-by: Adrien Grassein <adrien.grassein@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-nitrogen-r2.dts

@@ -247,6 +247,34 @@ &usdhc3 {
 	status = "okay";
 };
 
+/* USB OTG port */
+&usbotg1 {
+	dr_mode = "otg";
+	over-current-active-low;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usbotg1>;
+	power-active-high;
+	status = "okay";
+};
+
+/* USB Host port */
+&usbotg2 {
+	dr_mode = "host";
+	over-current-active-low;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usbotg2>;
+	power-active-high;
+	/*
+	 * FIXME: having USB2 enabled hangs the boot just after:
+	 *[    1.655941] ci_hdrc ci_hdrc.1: EHCI Host Controller
+	 *[    1.660880] ci_hdrc ci_hdrc.1: new USB bus registered, assigned bus number 2
+	 *[    1.681505] ci_hdrc ci_hdrc.1: USB 2.0 started, EHCI 1.00
+	 *[    1.687730] hub 2-0:1.0: USB hub found
+	 *[    1.691528] hub 2-0:1.0: 1 port detected
+	 */
+	status = "disabled";
+};
+
 &wdog1 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_wdog>;
@@ -318,6 +346,20 @@ MX8MM_IOMUXC_UART2_TXD_UART2_DCE_TX 0x140
 		>;
 	};
 
+	pinctrl_usbotg1: usbotg1grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_GPIO1_IO12_USB1_OTG_PWR	0x16
+			MX8MM_IOMUXC_GPIO1_IO13_USB1_OTG_OC	0x156
+		>;
+	};
+
+	pinctrl_usbotg2: usbotg2grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_GPIO1_IO14_USB2_OTG_PWR	0x16
+			MX8MM_IOMUXC_GPIO1_IO15_USB2_OTG_OC	0x15
+		>;
+	};
+
 	pinctrl_usdhc1: usdhc1grp {
 		fsl,pins = <
 			MX8MM_IOMUXC_SD1_CLK_USDHC1_CLK		0x190