drm/amdgpu: revert to old status lock handling v3

It turned out that protecting the status of each bo_va with a
spinlock was just hiding problems instead of solving them.

Revert the whole approach, add a separate stats_lock and lockdep
assertions that the correct reservation lock is held all over the place.

This not only allows for better checks if a state transition is properly
protected by a lock, but also switching back to using list macros to
iterate over the state of lists protected by the dma_resv lock of the
root PD.

v2: re-add missing check
v3: split into two patches

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>