media: mediatek: vcodec: Handle VP9 superframe bitstream with 8 sub-frames

The VP9 bitstream uses superframes, which each contain 8 sub-frames,
enable accessing the last superframe by increasing the range of the index
vaidation as the maximum number of superframes is 8 and not 7, so that the
last sub-frame can be decoded normally with the stateful VP9 decoder.

Signed-off-by: Irui Wang <irui.wang@mediatek.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mediatek: vcodec: separate decoder and encoder

Move all decoder files to folder decoder.
Move all encoder files to folder encoder.
Move common files which shared for encoder and decoder to folder common.

Change include header files and Makefile to fix build error.

Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>