[media] rtl28xxu: set correct FC2580 tuner for RTL2832 demod

rtl2832 demod driver has support for FC2580 tuner config, no need to
abuse FC0012 settings anymore.

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