Rename existing BBA to BBA (TAP) to prepare for new BBA

Based on work by tommy1019

Source/Core/Core/ConfigManager.h

@@ -226,7 +226,8 @@ struct SConfig
   std::string m_strGbaCartB;
   ExpansionInterface::TEXIDevices m_EXIDevice[3];
   SerialInterface::SIDevices m_SIDevice[4];
-  std::string m_bba_mac;
+
+  std::string m_bba_tap_mac;
 
   // interface language
   std::string m_InterfaceLanguage;