V4L/DVB (8634): v4l2: extend MPEG Encoding API with AVC and AAC

Adds Advanced Audio Coding (AAC) and MPEG-4 Advanced Video Coding
(AVC/H.264) as audio/video codecs to the extended controls API.
Updates cx2341x driver to the new values.

Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>