Add better comments for new adpf cpu multi-display patch

    RingBuffer<nsecs_t, 2> mCommitStartTimes;

    // Buffer of recent expected present times

    RingBuffer<nsecs_t, 2> mExpectedPresentTimes;

    // Most recent present fence time, set at the end of the frame once known

    // Most recent present fence time, provided by SF after composition engine finishes presenting

    nsecs_t mLastPresentFenceTime = -1;

    // Most recent present fence time, set at the end of the frame once known

    // Most recent composition engine present end time, returned with the present fence from SF

    nsecs_t mLastSfPresentEndTime = -1;

    // Target for the entire pipeline including gpu

    // Target duration for the entire pipeline including gpu

    std::optional<nsecs_t> mTotalFrameTargetDuration;

    // Updated list of display IDs

    std::vector<DisplayId> mDisplayIds;