BtAudio: Improve LE offload compatability

Bug: 203490261
Test: m android.hardware.bluetooth.audio-V1-impl
Change-Id: I7dd37cb697b03bb5fe0bdc467f8e190575e0e2e1
diff --git a/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h b/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h
index 85fd571..73bc0f8 100644
--- a/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h
+++ b/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h
@@ -144,7 +144,7 @@
    * The control function is for the bluetooth_audio module to get the current
    * AudioConfiguration
    ***/
-  const AudioConfiguration& GetAudioConfig();
+  const AudioConfiguration GetAudioConfig();
 
   /***
    * The report function is used to report that the Bluetooth stack has notified
@@ -173,14 +173,6 @@
   // Return if IBluetoothAudioProviderFactory implementation existed
   static bool IsAidlAvailable();
 
-  static constexpr PcmConfiguration kInvalidPcmConfiguration = {};
-  // can't be constexpr because of non-literal type
-  static const CodecConfiguration kInvalidCodecConfiguration;
-
-  static AudioConfiguration invalidSoftwareAudioConfiguration;
-  static AudioConfiguration invalidOffloadAudioConfiguration;
-  static AudioConfiguration invalidLeOffloadAudioConfig;
-
  private:
   // using recursive_mutex to allow hwbinder to re-enter again.
   std::recursive_mutex mutex_;