[media] cec/TODO: add TODO file so we know why this is still in staging

The reason why cec.c is still in staging is that I would like

to have a bit more confidence in the uABI. The kABI is fine,

no problem there, but I would like to let the public API mature

a bit.

Once I'm confident that I didn't miss anything then the cec.c source

can move to drivers/media and the linux/cec.h and linux/cec-funcs.h

headers can move to uapi/linux and added to uapi/linux/Kbuild to make

them public.

Hopefully this will happen later in 2016.

Other TODOs:

- Add a flag to inhibit passing CEC RC messages to the rc subsystem.

  Applications should be able to choose this when calling S_LOG_ADDRS.

- Convert cec.txt to sphinx.

- If the reply field of cec_msg is set then when the reply arrives it

  is only sent to the filehandle that transmitted the original message

  and not to any followers. Should this behavior change or perhaps

  controlled through a cec_msg flag?

- Should CEC_LOG_ADDR_TYPE_SPECIFIC be replaced by TYPE_2ND_TV and TYPE_PROCESSOR?

  And also TYPE_SWITCH and TYPE_CDC_ONLY in addition to the TYPE_UNREGISTERED?

  This should give the framework more information about the device type

  since SPECIFIC and UNREGISTERED give no useful information.

Hans Verkuil <hans.verkuil@cisco.com>