drm/ttm: fixup ttm_bo_add_move_fence v2

drm/ttm: fixup ttm_bo_add_move_fence v2

It looks like we still need to call dma_fence_put() on the man->move,
otherwise we just end up leaking it, leading to fireworks later.

v2(Daniel):
  - Simplify the function tail

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5689
Fixes: 8bb31587820a ("drm/ttm: remove bo->moving")
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220413082133.272445-1-matthew.auld@intel.com