media: Kconfig: move CEC-specific options to cec/Kconfig

There's no need to have the CEC definitions inside the
media Kconfig, as the Kconfig parser doesn't require
symbols to be declared before their usages.

With that, the main Kconfig menu becomes cleaner.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>