After 25167fb2, get_primary_monitor_rect()
maybe invalid before display device initialization or returns the desktop
rectangle after desktop initialization in virtual desktop mode, which is
wrong. The desktop size limit should come from host system.

This fixes a regression from efbbe666.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=47815Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>