drm/mediatek: Fix wrong dither settings

The width and height arguments in the cmdq packet for mtk_dither_config()
are inverted. We fix the incorrect width and height for dither settings
in mtk_dither_config().

Fixes: 73d37247

 ("drm/mediatek: Adjust to the alphabetic order for mediatek-drm")
Co-developed-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20220908141205.18256-1-allen-kh.cheng@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>