Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=56674
Now that we write all the display modes as a blob, we also write their header to the registry. This includes the dmSize field which is later used to iterate the modes after they've been read from the registry. The virtual desktop mode and some drivers were not setting it properly.
-- v2: winemac: Set DEVMODEW dmSize field. wineandroid: Set DEVMODEW dmSize field. win32u: Set DEVMODEW dmSize field.