media: platform: mtk-mdp3: cmdq: Remove duplicated platforms checks

The platform compatibility checks for MT8183 and
MT8195 in mdp_cmdq_prepare() are redundant as they are
done in __get_config_offset() itself. Furthermore
there are two if-else branch in __get_config_offset()
which have similar conditions and are redundant.
To address this, remove the check in mdp_cmdq_prepare()
and combine the two if-else branch into one in
__get_config_offset().

Signed-off-by: Mohammed Anees <pvmohammedanees2003@gmail.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>