FirstBootPrompt: focus the language list

Make it possible to easily use the window with only the keyboard.

src/apps/firstbootprompt/BootPromptWindow.cpp

@@ -215,6 +215,8 @@ BootPromptWindow::BootPromptWindow()
 		.View()
 	);
 
+	fLanguagesListView->MakeFocus();
+
 	_UpdateStrings();
 	CenterOnScreen();
 	Show();