ARM: dts: meson8b: odroidc1: add iio-hwmon for the chip temperature

SAR ADC enabled channel 8 can be used to measure the chip temperature.
This can be made available to the hwmon subsystem by using iio-hwmon.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm/boot/dts/meson8b-odroidc1.dts

@@ -118,6 +118,11 @@ tf_io: gpio-regulator-tf_io {
 			  1800000 1>;
 	};
 
+	iio-hwmon {
+		compatible = "iio-hwmon";
+		io-channels = <&saradc 8>;
+	};
+
 	vcc_1v8: regulator-vcc-1v8 {
 		/*
 		 * RICHTEK RT9179 configured for a fixed output voltage of