media: mtk-vcodec: Add MT8192 H264 venc driver

Add MT8192 venc driver's compatible and device private data.

Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Signed-off-by: Irui Wang <irui.wang@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>