Kill directx < 9 ifdefery

Baseline is Windows XP and SP3 includes directx 9.0c

Change-Id: Ib7095ebb71f297898ae8b316e3b9f18e7c052f34
Reviewed-on: https://gerrit.libreoffice.org/12246
Tested-by: LibreOffice gerrit bot <gerrit@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>