qt: Default destructors where applicable

Makes code consistent with our style of defaulting special member
functions where applicable.

src/yuzu/configuration/configure_system.cpp

@@ -35,7 +35,7 @@ ConfigureSystem::ConfigureSystem(QWidget* parent) : QWidget(parent), ui(new Ui::
     this->setConfiguration();
 }
 
-ConfigureSystem::~ConfigureSystem() {}
+ConfigureSystem::~ConfigureSystem() = default;
 
 void ConfigureSystem::setConfiguration() {
     enabled = !Core::System::GetInstance().IsPoweredOn();