GeckoCode: Remove Dead Code

Source/Core/Core/GeckoCode.cpp

@@ -45,14 +45,6 @@ bool operator!=(const GeckoCode::Code& lhs, const GeckoCode::Code& rhs)
   return !operator==(lhs, rhs);
 }
 
-// return true if a code exists
-bool GeckoCode::Exist(u32 address, u32 data) const
-{
-  return std::find_if(codes.begin(), codes.end(), [&](const Code& code) {
-           return code.address == address && code.data == data;
-         }) != codes.end();
-}
-
 enum class Installation
 {
   Uninstalled,

Source/Core/Core/GeckoCode.h

@@ -36,8 +36,6 @@ public:
   bool enabled = false;
   bool default_enabled = false;
   bool user_defined = false;
-
-  bool Exist(u32 address, u32 data) const;
 };
 
 bool operator==(const GeckoCode& lhs, const GeckoCode& rhs);