Kill unused directx < 9 ifdefery

Change-Id: I2cd5dd5b4f723e26802930003c68433917af782d
Reviewed-on: https://gerrit.libreoffice.org/13371
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>