[media] media: Fix DVB devnode representation at media controller

[media] media: Fix DVB devnode representation at media controller

The previous provision for DVB media controller support were to
define an ID (likely meaning the adapter number) for the DVB
devnodes.

This is just plain wrong. Just like V4L, DVB devices (and any other
device node)) are uniquely identified via a (major, minor) tuple.

This is enough to uniquely identify a devnode, no matter what
API it implements.

So, before we go too far, let's mark the old v4l, fb, dvb and alsa
"devnode" info as deprecated, and just call it as "dev".

We can latter add fields specific to each API if needed.

As we don't want to break compilation on already existing apps,
let's just keep the old definitions as-is, adding a note that
those are deprecated at media-entity.h.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>