arm64: dts: imx8mn-evk: Pass GPIO_OPEN_DRAIN flag

scl-gpios and sda-gpios need GPIO_OPEN_DRAIN flag, otherwise the
following run-time warning is seen:

gpio-144 (scl): enforced open drain please flag it properly in DT/ACPI DSDT/board file
gpio-146 (scl): enforced open drain please flag it properly in DT/ACPI DSDT/board file
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

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

@@ -163,8 +163,8 @@ &i2c2 {
 	pinctrl-names = "default", "gpio";
 	pinctrl-0 = <&pinctrl_i2c2>;
 	pinctrl-1 = <&pinctrl_i2c2_gpio>;
-	scl-gpios = <&gpio5 16 GPIO_ACTIVE_HIGH>;
-	sda-gpios = <&gpio5 17 GPIO_ACTIVE_HIGH>;
+	scl-gpios = <&gpio5 16 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+	sda-gpios = <&gpio5 17 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 	status = "okay";
 
 	ptn5110: tcpc@50 {