media: mediatek: vcodec: Use 4K frame size when supported by stateful decoder

After commit b018be06 ("media: mediatek: vcodec: Read max resolution
from dec_capability"), the stateful video decoder driver never really
sets its output frame size to 4K.

Parse the decoder capability reported by the firmware, and update the
output frame size in mtk_init_vdec_params to enable 4K frame size when
available.

Fixes: b018be06 ("media: mediatek: vcodec: Read max resolution from dec_capability")
Signed-off-by: Pin-yen Lin <treapking@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>