[media] rtl28xxu: support for the rtl2832 demod driver

This only adds support for the Terratec Cinergy T Stick Black device.

Changes from previous patches:
- fixed compiler warnings
- added fc0013 tuner handling to this patch

Signed-off-by: Thomas Mair <thomas.mair86@googlemail.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>