drm/atomic: add private obj state to state dump

The drm_atomic_print_new_state() already prints private object state via
drm_atomic_private_obj_print_state(). Add private object state dumping
to __drm_state_dump(), so that it is also included into drm_state_dump()
output and into debugfs/dri/N/state file.

Reviewed-by: Rob Clark <robdclark@gmail.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231203000532.1290480-2-dmitry.baryshkov@linaro.org