SceneGraph: remove forward declaration for deprecated enum.

There was no point in using it anywhere else than when passing it to the
transformation function itself.

src/Magnum/SceneGraph/SceneGraph.h

@@ -64,10 +64,6 @@ template<class T> using AbstractBasicObject3D = AbstractObject<3, T>;
 typedef AbstractBasicObject2D<Float> AbstractObject2D;
 typedef AbstractBasicObject3D<Float> AbstractObject3D;
 
-#ifdef MAGNUM_BUILD_DEPRECATED
-enum class TransformationType: UnsignedByte;
-#endif
-
 template<UnsignedInt, class> class AbstractTransformation;
 template<class T> using AbstractBasicTransformation2D = AbstractTransformation<2, T>;
 template<class T> using AbstractBasicTransformation3D = AbstractTransformation<3, T>;