media: mediatek: vcodec: Setting lat buf to lat_list when lat decode error

Need to set lat buf to lat_list when lat decode error, or lat buffer will
be lost.

Fixes: 5d418351 ("media: mediatek: vcodec: support stateless VP9 decoding")
Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
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>