[media] rtl28xxu: add support for RTL2831U/RTL2830 PID filter

RTL2830 demod integrated to RTL2831U has PID filter. PID filtering
is provided by rtl2830 demod driver. Add support for it.

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