drm/bridge: analogix_dp: ignore return values of drm_panel_* calls

Follow the example of other drivers and ignore return values of the
drm_panel_prepare() / unprepare() / enable() / disable() calls. There is
no possible error recovery, so the driver just logs a message.

Tested-by: Damon Ding <damon.ding@rock-chips.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250401-panel-return-void-v1-6-93e1be33dc8d@oss.qualcomm.com


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