dt-bindings: Add thermal zone to bcm2835-thermal example

Add a thermal zone in order to make the example complete.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>

Documentation/devicetree/bindings/thermal/brcm,bcm2835-thermal.txt

@@ -3,15 +3,39 @@ Binding for Thermal Sensor driver for BCM2835 SoCs.
 Required parameters:
 -------------------
 
-compatible: 	should be one of: "brcm,bcm2835-thermal",
-		"brcm,bcm2836-thermal" or "brcm,bcm2837-thermal"
-reg:		Address range of the thermal registers.
-clocks: 	Phandle of the clock used by the thermal sensor.
+compatible: 		should be one of: "brcm,bcm2835-thermal",
+			"brcm,bcm2836-thermal" or "brcm,bcm2837-thermal"
+reg:			Address range of the thermal registers.
+clocks: 		Phandle of the clock used by the thermal sensor.
+#thermal-sensor-cells:	should be 0 (see thermal.txt)
 
 Example:
 
+thermal-zones {
+	cpu_thermal: cpu-thermal {
+		polling-delay-passive = <0>;
+		polling-delay = <1000>;
+
+		thermal-sensors = <&thermal>;
+
+		trips {
+			cpu-crit {
+				temperature	= <80000>;
+				hysteresis	= <0>;
+				type		= "critical";
+			};
+		};
+
+		coefficients = <(-538)	407000>;
+
+		cooling-maps {
+		};
+	};
+};
+
 thermal: thermal@7e212000 {
 	compatible = "brcm,bcm2835-thermal";
 	reg = <0x7e212000 0x8>;
 	clocks = <&clocks BCM2835_CLOCK_TSENS>;
+	#thermal-sensor-cells = <0>;
 };