【需求】双网络类型通过长按boot切换网络 (#520)

* 【需求】双网络类型通过长按boot切换网络

* Update Kconfig.projbuild

---------

Co-authored-by: guhaibo <guhaibo@boe.com.cn>
Co-authored-by: Xiaoxia <terrence@tenclass.com>

main/boards/common/ml307_board.h

@@ -7,7 +7,6 @@
 class Ml307Board : public Board {
 protected:
     Ml307AtModem modem_;
-
     virtual std::string GetBoardJson() override;
     void WaitForNetworkReady();
 
@@ -21,6 +20,7 @@ public:
     virtual Udp* CreateUdp() override;
     virtual const char* GetNetworkStateIcon() override;
     virtual void SetPowerSaveMode(bool enabled) override;
+    virtual AudioCodec* GetAudioCodec() override { return nullptr; }
 };
 
 #endif // ML307_BOARD_H