media: cec: expose the new connector info API

Until now the connector info API was a kernel-internal API only.
This moves it to the public API and adds the new ioctl to retrieve
this information.

Signed-off-by: Dariusz Marcinkiewicz <darekm@google.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>