[media] dvbsky: use si2168 config option ts_clock_gapped

Change the dvbsky driver to support gapped clock instead of the current
hack.

Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>