leaved content unchanged, only improved markup and references

* more man-like sections (add Name section)
* defined target for each stuct field description
* replace constant with ":ref:" to (field) description
Signed-off-by: NMarkus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

This is the reST migration of media's CEC part.  The migration is based
on media_tree's cec branch:

 https://git.linuxtv.org/media_tree.git

 c7169ad5 * cec media_tree/cec [media] DocBook/media: add CEC documentation
Signed-off-by: NMarkus Heiser <markus.heiser@darmarIT.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

Changeset 811c6d6a ("[media] V4L: fix the Z16 format definition")
fixed the definition for DocBook, but we need to replicate it
also to ReST.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

Changeset 8c9f46095176 ("[media] DocBook: mention the memory type to
be set for all streaming I/O") updated the media DocBook to mention
the need of filling the memory types. We need to keep the ReST
doc updated to such change.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

Commit 707e65831d3b("[media] DocBook: add dmabuf as streaming I/O
in VIDIOC_REQBUFS description") added DMABUF to reqbufs description,
but, as we're migrating to ReST markup, we need to keep it in sync
with the change.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>

The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.

No functional changes.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>