[media] v4l: Group media bus pixel codes by types and sort them alphabetically

Adding new pixel codes at the end of the enumeration will soon create a
mess, so group the pixel codes by type and sort them by bus_width, bits
per component, samples per pixel and order of subsamples.

As the codes are part of the kernel ABI their value can't change when a
new code is inserted in the enumeration, so they are given an explicit
numerical value. When inserting a new pixel code developers must use and
update the next free value.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>