[media] rtl2832: add support for slave ts pid filter

The rtl2832 demod has 2 sets of PID filters. This patch enables
the filter support when using a slave demod.

Signed-off-by: Benjamin Larsson <benjamin@southpole.se>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>