[media] rtl28xxu: use platform data config for rtl2832 demod

Use platform data configuration for rtl2832 demod driver. Old
configuration are still left as it is used for rtl2832_sdr driver.

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