Add documentation for 3 formats, used by RealSense cameras like R200. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>