media: mediatek: vcodec: Fix kerneldoc

Those fields have been removed. They do not need to be documented.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>