am d61ba0aa: am 36d9256f: am ac302143: Fix the fix

    if (getEffectChain_l(AUDIO_SESSION_OUTPUT_MIX) != 0) {

        mEffectBufferValid = true;

    }

    if (mEffectBufferValid) {

        // as long as there are effects we should clear the effects buffer, to avoid

        // passing a non-clean buffer to the effect chain

        memset(mEffectBuffer, 0, mEffectBufferSize);

    }

    // sink or mix buffer must be cleared if all tracks are connected to an

    // effect chain as in this case the mixer will not write to the sink or mix buffer

    // and track effects will accumulate into it