Mac driver version of a8b4cf7f.

Combined with the previous patch that reordered synthesized modes,
the Mac driver implementation of EnumDisplayModesEx now returns modes
in the same order as the X11 driver.
Signed-off-by: Tim Clem <tclem@codeweavers.com>
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>