media: vidtv: Add media controller support

Add media controller support when CONFIG_MEDIA_CONTROLLER_DVB is set
so that, in the future, a test sequence in v4l-utils can be written
without having to know which /dev/fooX device should be used.

[mchehab: avoided usage of C99 comments]
Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>