media: MAINTAINERS: media: cec: fix files location

Files have moved, fixes their paths.

Fixes: 4be5e864 ("media: move CEC platform drivers to a separate directory")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>