Instead of going backward, which breaks the Linux kernel transparent
huge pages allocation assumptions.

This can be reproduced by calling memset on large, newly allocated,
memory regions.
Signed-off-by: Rémi Bernon <rbernon@codeweavers.com>
Signed-off-by: Piotr Caban <piotr@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>