media: mediatek: vcodec: Read max resolution from dec_capability

Supported max resolution for different platforms are not the same: 2K
or 4K, getting it according to dec_capability.

Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: Tzung-Bi <Shih&lt;tzungbi@google.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>