[media] cec-edid: add module for EDID CEC helper functions

The cec-edid module contains helper functions to find and manipulate
the CEC physical address inside an EDID. Even if the CEC support itself
is disabled, drivers will still need these functions. Which is the
reason this is module is separate from the upcoming CEC framework.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>