d3dx9: Don't always fail if an ID3DXAnimationController pointer is passed to D3DXLoadMeshHierarchyFromXInMemory.

D3DXLoadMeshHierarchyFromXInMemory will only return an AnimationController
when the xfile has an AnimationSet.
Signed-off-by: Alistair Leslie-Hughes <leslie_alistair@hotmail.com>
Signed-off-by: Matteo Bruni <mbruni@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>