drm/bridge: cdns-dsi: Move to devm_drm_of_get_bridge()

Instead of manually finding the next bridge/panel, and maintaining the
panel-bridge (in-case the next entity is a panel), switch to using the
automatically managing devm_drm_of_get_bridge() API.

Drop the drm_panel support completely from the driver while at it.

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Link: https://lore.kernel.org/r/20250329113925.68204-7-aradhya.bhatia@linux.dev


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>