Implemented Citra Enhanced's realtime audio option

Co-authored-by: Gamer64ytb <76565986+Gamer64ytb@users.noreply.github.com>

src/core/core.cpp

@@ -391,6 +391,10 @@ PerfStats::Results System::GetLastPerfStats() {
     return perf_stats ? perf_stats->GetLastStats() : PerfStats::Results{};
 }
 
+double System::GetLastFrameTimeScale() {
+    return perf_stats->GetLastFrameTimeScale();
+}
+
 void System::Reschedule() {
     if (!reschedule_pending) {
         return;

src/core/core.h

@@ -184,6 +184,8 @@ public:
 
     [[nodiscard]] PerfStats::Results GetLastPerfStats();
 
+    double GetLastFrameTimeScale();
+
     /**
      * Gets a reference to the emulated CPU.
      * @returns A reference to the emulated CPU.