media: Kconfig: Make DVB_CORE=m possible when MEDIA_SUPPORT=y

A case that CONFIG_MEDIA_SUPPORT is y but we need DVB_CORE=m, and
this doesn't work since DVB_CORE is default MEDIA_DIGITAL_TV_SUPPORT
and then follows MEDIA_SUPPORT.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>