media: mtk-vcodec: Clean redundant encoder format definition

The supported capture/output formats don't depend on models,
clean redundant definitions and naming with type instead.

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>