Boxlite aec (#465)

* 允许espbox-lite打开aec
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* 软件回声消除

* 支持双麦采集

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Co-authored-by: cqm <cqm@97kid.com>

main/boards/esp-box-lite/box_audio_codec_lite.h

@@ -17,6 +17,10 @@ private:
 
     esp_codec_dev_handle_t output_dev_ = nullptr;
     esp_codec_dev_handle_t input_dev_ = nullptr;
+    // ref buffer used for aec
+    std::vector<int16_t> ref_buffer_;
+    int read_pos_ = 0;
+    int write_pos_ = 0;
 
     void CreateDuplexChannels(gpio_num_t mclk, gpio_num_t bclk, gpio_num_t ws, gpio_num_t dout, gpio_num_t din);