media: v4l: Documentation: Raw Bayer formats are not RGB formats

The raw Bayer formats have been listed under the label of RGB formats but
in fact they're quite different. The latter are readily usable as such
whereas the former require quite bit of image processing before useful.

Split them into RGB and raw Bayer formats.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>