ARM: tegra: colibri_t20: iris: integrate i2c real time clock support

Integrate support for GEN1_I2C aka I2C_SDA/SCL on SODIMM pin 194/196 and
the M41T0M6 real time clock on the carrier board.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-colibri-iris.dts

@@ -56,6 +56,21 @@ serial@70006300 {
 		status = "okay";
 	};
 
+	/*
+	 * GEN1_I2C: I2C_SDA/SCL on SODIMM pin 194/196 (e.g. RTC on carrier
+	 * board)
+	 */
+	i2c@7000c000 {
+		status = "okay";
+		clock-frequency = <400000>;
+
+		/* M41T0M6 real time clock on carrier board */
+		rtc@68 {
+			compatible = "st,m41t0";
+			reg = <0x68>;
+		};
+	};
+
 	i2c_ddc: i2c@7000c400 {
 		status = "okay";
 	};