Qt: Don't force a minimum size for the main window

Source/Core/DolphinQt2/MainWindow.cpp

@@ -259,7 +259,6 @@ void MainWindow::ConnectRenderWidget()
 
 void MainWindow::ConnectStack()
 {
-  m_stack->setMinimumSize(800, 600);
   m_stack->addWidget(m_game_list);
   setCentralWidget(m_stack);
 }
@@ -621,3 +620,8 @@ void MainWindow::dropEvent(QDropEvent* event)
     settings.AddPath(path);
   }
 }
+
+QSize MainWindow::sizeHint() const
+{
+  return QSize(800, 600);
+}

Source/Core/DolphinQt2/MainWindow.h

@@ -89,6 +89,7 @@ private:
 
   void dragEnterEvent(QDragEnterEvent* event) override;
   void dropEvent(QDropEvent* event) override;
+  QSize sizeHint() const override;
 
   QStackedWidget* m_stack;
   ToolBar* m_tool_bar;