NVIDIA Tegra186 BPMP thermal sensor

In Tegra186, the BPMP (Boot and Power Management Processor) implements an
interface that is used to read system temperatures, including CPU cluster
and GPU temperatures. This binding describes the thermal sensor that is
exposed by BPMP.

The BPMP thermal node must be located directly inside the main BPMP node. See
../firmware/nvidia,tegra186-bpmp.txt for details of the BPMP binding.

This node represents a thermal sensor. See thermal.txt for details of the
core thermal binding.

Required properties:
- compatible:
    Array of strings.
    One of:
    - "nvidia,tegra186-bpmp-thermal"
    - "nvidia,tegra194-bpmp-thermal"
- #thermal-sensor-cells: Cell for sensor index.
    Single-cell integer.
    Must be <1>.

Example:

bpmp {
	...

	bpmp_thermal: thermal {
		compatible = "nvidia,tegra186-bpmp-thermal";
		#thermal-sensor-cells = <1>;
	};
};