V4L/DVB(7767): Move tuners to common/tuners

There were several issues in the past, caused by the hybrid tuner design, since
now, the same tuner can be used by drivers/media/dvb and drivers/media/video.

Kconfig items were rearranged, to split V4L/DVB core from their drivers.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>