[media] media: Remove VIDEO_MEDIA Kconfig option

In the past, it was possible to have either DVB or V4L2 core
as module and the other as builtin. Such config never make much
sense, and created several issues in order to make the Kconfig
dependency to work, as all drivers that depend on both (most
TV drivers) would need to be compiled as 'm'. Due to that,
the VIDEO_MEDIA config option were added.

Instead of such weird approach, let's just use the MEDIA_SUPPORT
=y or =m to select if the media subsystem core will be either
builtin or module, simplifying the building system logic.

Also, fix the tuners configuration, by enabling them only if
a tuner is required. So, if just webcam/grabbers support is
selected, no tuner option will be selected. Also, if only digital
TV is selected, no analog tuner support is selected.

That removes the need of using EXPERT customise options, when
analog TV is not selected.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>