ARM: shmobile: henninger: add I2C2 DT support

Define the Henninger board dependent part of the I2C2 device node.

Based on the Koelsch I2C2 device tree patch by Wolfram Sang.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791-henninger.dts

@@ -110,6 +110,11 @@
 		renesas,function = "sdhi2";
 	};
 
+	i2c2_pins: i2c2 {
+		renesas,groups = "i2c2";
+		renesas,function = "i2c2";
+	};
+
 	qspi_pins: spi0 {
 		renesas,groups = "qspi_ctrl", "qspi_data4";
 		renesas,function = "qspi";
@@ -170,6 +175,14 @@
 	status = "okay";
 };
 
+&i2c2 {
+	pinctrl-0 = <&i2c2_pins>;
+	pinctrl-names = "default";
+
+	status = "okay";
+	clock-frequency = <400000>;
+};
+
 &qspi {
 	pinctrl-0 = <&qspi_pins>;
 	pinctrl-names = "default";