yuzu/bootmanager: Default EmuThread's destructor in the cpp file

This class contains non-trivial members, so we should default the
destructor's definition within the cpp file.

src/yuzu/bootmanager.cpp

@@ -26,6 +26,8 @@
 
 EmuThread::EmuThread(GRenderWindow* render_window) : render_window(render_window) {}
 
+EmuThread::~EmuThread() = default;
+
 void EmuThread::run() {
     render_window->MakeCurrent();
 

src/yuzu/bootmanager.h

@@ -27,11 +27,12 @@ namespace VideoCore {
 enum class LoadCallbackStage;
 }
 
-class EmuThread : public QThread {
+class EmuThread final : public QThread {
     Q_OBJECT
 
 public:
     explicit EmuThread(GRenderWindow* render_window);
+    ~EmuThread() override;
 
     /**
      * Start emulation (on new thread)