arm64: dts: imx8mn-evk: Add i2c3 support

Enable i2c3 for i.MX8MN EVK board.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mn-evk.dtsi

@@ -102,6 +102,13 @@ typec1_con: connector {
 	};
 };
 
+&i2c3 {
+	clock-frequency = <400000>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_i2c3>;
+	status = "okay";
+};
+
 &snvs_pwrkey {
 	status = "okay";
 };
@@ -202,6 +209,13 @@ MX8MN_IOMUXC_I2C2_SDA_I2C2_SDA		0x400001c3
 		>;
 	};
 
+	pinctrl_i2c3: i2c3grp {
+		fsl,pins = <
+			MX8MN_IOMUXC_I2C3_SCL_I2C3_SCL		0x400001c3
+			MX8MN_IOMUXC_I2C3_SDA_I2C3_SDA		0x400001c3
+		>;
+	};
+
 	pinctrl_reg_usdhc2_vmmc: regusdhc2vmmc {
 		fsl,pins = <
 			MX8MN_IOMUXC_SD2_RESET_B_GPIO2_IO19	0x41