drm/amdgpu: set bulk_moveable to false when lru changed v2

if lru is changed, we cannot do bulk moving.
v2:
root bo isn't in bulk moving, skip its change.

Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>