media: uapi: v4l: Add generic 8-bit metadata format definitions

media: uapi: v4l: Add generic 8-bit metadata format definitions

Generic 8-bit metadata formats define the in-memory data layout but not
the format of the data itself. The reasoning for having such formats is to
allow CSI-2 receiver drivers to receive and DMA drivers to write the data
to memory without knowing a large number of device-specific formats.

These formats may be used only in conjunction with a Media Controller
pipeline where the internal pad of the source sub-device defines the
specific format of the data (using an mbus code).

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>