Merge "AudioFlinger: update primaryPlaybackThread_l() getter" into main

IAfPlaybackThread* AudioFlinger::primaryPlaybackThread_l() const

{

    audio_utils::lock_guard lock(hardwareMutex());

    // The atomic ptr mPrimaryHardwareDev requires both the

    // AudioFlinger and the Hardware mutex for modification.

    // As we hold the AudioFlinger mutex, we access it

    // safely without the Hardware mutex, to avoid mutex order

    // inversion with Thread methods and the ThreadBase mutex.

    if (mPrimaryHardwareDev == nullptr) {

        return nullptr;

    }