mt6735 产线加大MIC2测试声音

[DESCRIPTION]
在产线，测试发现MIC2声音比较小，基本都听不到，需要加大测试
[SOLUTION]
修改方法如下:
对于MIC的设定最大为kPreAmpGainMapValue[PREAMP_GAIN_32_DB]
AudioLoopbackController.cpp中OpenAudioLoopbackControlFlow()
#ifdef AUDIO_LOOPBACK_USE_MAX_GAIN
// adjust downlink volume for current mode and routes
mMasterVolumeCopy = mAudioVolumeInstance->getMasterVolume();
int normal_mode = android_audio_legacy::AudioSystem::MODE_NORMAL;
mAudioVolumeInstance->setMasterVolume(kMaxMasterVolume, normal_mode, output_device);
// adjust uplink volume for current mode and routes
MMIcAmPLChGainCopy = mAudioAnalogInstance->GetAnalogGain(AudioAnalogType::VOLUME_MICAMPL);
mMicAmpRchGainCopy = mAudioAnalogInstance->GetAnalogGain(AudioAnalogType::VOLUME_MICAMPR);
if (output_device == android_audio_legacy::AudioSystem:EVICE_OUT_SPEAKER) {
mAudioAnalogInstance->SetAnalogGain(AudioAnalogType::VOLUME_MICAMPL,
kPreAmpGainMapValue[PREAMP_GAIN_8_DB]);
mAudioAnalogInstance->SetAnalogGain(AudioAnalogType::VOLUME_MICAMPR,
kPreAmpGainMapValue[PREAMP_GAIN_8_DB]);
}
else {
mAudioAnalogInstance->SetAnalogGain(AudioAnalogType::VOLUME_MICAMPL,
kPreAmpGainMapValue[PREAMP_GAIN_26_DB]);
mAudioAnalogInstance->SetAnalogGain(AudioAnalogType::VOLUME_MICAMPR,
kPreAmpGainMapValue[PREAMP_GAIN_26_DB]);
}
#endif