core: Eliminate more uses of Core::System::GetInstance(). (#7313)

src/audio_core/hle/hle.cpp

@@ -24,16 +24,10 @@
 #include "core/core.h"
 #include "core/core_timing.h"
 
-SERIALIZE_EXPORT_IMPL(AudioCore::DspHle)
-
 using InterruptType = Service::DSP::InterruptType;
 
 namespace AudioCore {
 
-DspHle::DspHle()
-    : DspHle(Core::System::GetInstance(), Core::System::GetInstance().Memory(),
-             Core::System::GetInstance().CoreTiming()) {}
-
 DspHle::DspHle(Core::System& system) : DspHle(system, system.Memory(), system.CoreTiming()) {}
 
 template <class Archive>

src/audio_core/hle/hle.h

@@ -50,13 +50,9 @@ private:
     friend struct Impl;
     std::unique_ptr<Impl> impl;
 
-    DspHle();
-
     template <class Archive>
     void serialize(Archive& ar, const unsigned int);
     friend class boost::serialization::access;
 };
 
 } // namespace AudioCore
-
-BOOST_CLASS_EXPORT_KEY(AudioCore::DspHle)