arm64: dts: freescale: imx8mm-phyboard: Add I2C4 pinmuxing

The I2C4 bus is exposed on the camera connector. Add and select the
corresponding pinmux entries and set the default frequency. The device
is left disabled, to be enabled from camera overlays.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Teresa Remmet <t.remmet@phytec.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-phyboard-polis-rdk.dts

@@ -168,6 +168,12 @@ &gpio5 {
 		"", "ECSPI1_SS0";
 };
 
+&i2c4 {
+	clock-frequency = <400000>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_i2c4>;
+};
+
 /* PCIe */
 &pcie0 {
 	assigned-clocks = <&clk IMX8MM_CLK_PCIE1_AUX>,
@@ -333,6 +339,13 @@ MX8MM_IOMUXC_SAI1_RXD6_GPIO4_IO8	0x16
 		>;
 	};
 
+	pinctrl_i2c4: i2c4grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_I2C4_SCL_I2C4_SCL		0x400001c2
+			MX8MM_IOMUXC_I2C4_SDA_I2C4_SDA		0x400001c2
+		>;
+	};
+
 	pinctrl_leds: leds1grp {
 		fsl,pins = <
 			MX8MM_IOMUXC_GPIO1_IO01_GPIO1_IO1	0x16