drm/ttm/drivers: remove unecessary ttm_module.h include v2

ttm_module.h deals with internals of TTM and should never
be include outside of it.

v2: also move the file around

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/404885/