ARM: tegra: Add i2c-bus subnode for DPAUX controllers

The DPAUX controller device tree bindings require the bus to have an
i2c-bus subnode to distinguish between I2C clients and pinmux groups.

Signed-off-by: Thierry Reding <[e-mail]>

arch/arm/boot/dts/tegra124.dtsi

···
 			resets = <&tegra_car 181>;
 			reset-names = "dpaux";
 			status = "disabled";
+
+			i2c-bus {
+				#address-cells = <1>;
+				#size-cells = <0>;
+			};
 		};
 	};