drm/mediatek: Adjust to the alphabetic order for mediatek-drm

Adjust to the alphabetic order for the define, function, struct
and array in mediatek-drm driver

Signed-off-by: jason-jh.lin <jason-jh.lin@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>