Update TouchEventReported docs

message TouchEventReported {

    /**

     * The fields latency_{min|max|mean|stdev} represent minimum, maximum, mean,

     * and the standard deviation of latency between the kernel and framework

     * for touchscreen events. The units are microseconds.

     *

     * The number is measured as the difference between the time at which

     * the input event was received in the evdev driver,

     * and the time at which the input event was received in EventHub.

     * and the standard deviation of the time spent processing touchscreen events

     * in the kernel and inputflinger. The units are microseconds.

     *

     * On supported devices, the starting point is taken during the hard interrupt inside the

     * kernel touch driver. On all other devices, the starting point is taken inside

     * the kernel's input event subsystem upon receipt of the input event.

     * The ending point is taken inside InputDispatcher, just after the input event

     * is sent to the app.

     */

    // Minimum value

    optional float latency_min_micros = 1;

        return mInputConsumer.getChannel()->getName();

    }

    virtual int handleEvent(int receiveFd, int events, void* data);

    virtual int handleEvent(int receiveFd, int events, void* data) override;

};