Update thermal headroom listener API doc for NDK

 * Prototype of the function that is called when thermal headroom or thresholds changes.

 * It's passed the updated thermal headroom and thresholds as parameters, as well as the

 * pointer provided by the client that registered a callback.

 * <p>

 * This may not be used to fully replace the {@link AThermal_getThermalHeadroom} API as it will

 * only notify on one of the conditions below that will significantly change one or both

 * values of current headroom and headroom thresholds since previous callback:

 *   1. thermal throttling events: when the skin temperature has cross any of the thresholds

 *      and there isn't a previous callback in a short time ago with similar values.

 *   2. skin temperature threshold change events: note that if the absolute °C threshold

 *      values change in a way that does not significantly change the current headroom nor

 *      headroom thresholds, it will not trigger any callback. The client should not

 *      need to take action in such case since the difference from temperature vs threshold

 *      hasn't changed.

 * <p>

 * By API version 36, it provides a forecast in the same call for developer's convenience

 * based on a {@code forecastSeconds} defined by the device, which can be static or dynamic

 * varied by OEM. Be aware that it will not notify on forecast temperature change but the

 * events mentioned above. So periodically polling against {@link AThermal_getThermalHeadroom}

 * API should still be used to actively monitor temperature forecast in advance.

 * <p>

 * This serves as a more advanced option compared to thermal status listener, where the

 * latter will only notify on thermal throttling events with status update.

 *

 * @param data The data pointer to be passed when callback is called.

 * @param headroom The current non-negative normalized headroom value, also see