drm/mediatek: dsi: Add dsi cmdq_ctl to send panel initial code

For mt8188, add dsi cmdq reg control to send long packets to panel
initialization. MT8188 hardware has been changed to automatically
set the cmdq_size value by default when sending long packets.
In this patch, the cmdq_size value is set manually instead.
Remain consistent with previous IC.

Signed-off-by: Shuijing Li <shuijing.li@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230911120800.17369-3-shuijing.li@mediatek.com/


Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>