[media] videodev2.h: Group YUV 3 planes formats together

The formats are interleaved with the YUV packed and miscellaneous
formats, making the result confusing especially with the YUV444 format
being packed and not planar like YUV410 or YUV420. Move them to their
own group as the 2 planes or 3 non-contiguous planes formats to clarify
the header.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>