V4L/DVB (8060): Kconfig: MEDIA_TUNER_CUSTOMIZE should be disabled by default

The build option, MEDIA_TUNER_CUSTOMIZE, allows us to disable tuner drivers
that would have otherwise been selected by default.  This is an advanced
customization option that should be disabled by default.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>