[media] media: au0828 - embed vdev and vbi_dev structs in au0828_dev

Embed video_device structs vdev and vbi_dev in au0828_dev.
With this change, dynamic allocation and error path logic
in au0828_analog_register() is removed as it doesn't need
to allocate and handle allocation errors. Unregister path
doesn't need to free the now static video_device structures,
hence, changed video_device.release in au0828_video_template
to point to video_device_release_empty.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>