drm/rockchip: analogix_dp: Add support to get panel from the DP AUX bus

drm/rockchip: analogix_dp: Add support to get panel from the DP AUX bus

Move drm_of_find_panel_or_bridge() a little later and combine it with
component_add() into a new function rockchip_dp_link_panel(). The function
will serve as done_probing() callback of devm_of_dp_aux_populate_bus(),
aiding to support for obtaining the eDP panel via the DP AUX bus.

If failed to get the panel from the DP AUX bus, it will then try the other
way to get panel information through the platform bus.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250310104114.2608063-9-damon.ding@rock-chips.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>