Qt: fix game list table multiselection

Apparently table items need one common role set for internal indexing.

rpcs3/rpcs3qt/movie_item.cpp

@@ -3,12 +3,15 @@
 
 movie_item::movie_item() : QTableWidgetItem(), movie_item_base()
 {
+	setData(Qt::UserRole, {}); // Set any value to UserRole for proper indexing (e.g. for multiselection)
 }
 
 movie_item::movie_item(const QString& text, int type) : QTableWidgetItem(text, type), movie_item_base()
 {
+	setData(Qt::UserRole, {}); // Set any value to UserRole for proper indexing (e.g. for multiselection)
 }
 
 movie_item::movie_item(const QIcon& icon, const QString& text, int type) : QTableWidgetItem(icon, text, type), movie_item_base()
 {
+	setData(Qt::UserRole, {}); // Set any value to UserRole for proper indexing (e.g. for multiselection)
 }

rpcs3/rpcs3qt/savestate_manager_dialog.cpp

@@ -85,6 +85,7 @@ savestate_manager_dialog::savestate_manager_dialog(std::shared_ptr<gui_settings>
 	m_savestate_table->horizontalScrollBar()->setSingleStep(20);
 	m_savestate_table->setItemDelegate(new table_item_delegate(m_savestate_table, false));
 	m_savestate_table->setSelectionBehavior(QAbstractItemView::SelectRows);
+	m_savestate_table->setSelectionMode(QAbstractItemView::SingleSelection);
 	m_savestate_table->setEditTriggers(QAbstractItemView::NoEditTriggers);
 	m_savestate_table->setColumnCount(static_cast<int>(gui::savestate_list_columns::count));
 	m_savestate_table->horizontalHeader()->setDefaultAlignment(Qt::AlignLeft);