Fixes a regression introduced by 308a5e7c.

This was previously broken, but happened to work until the aforementioned
commit put the YMM state right at the end of a page.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=51262Signed-off-by: Zebediah Figura <z.figura12@gmail.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>