[media] rtl28xxu: add [1b80:d39d] Sveon STV20

Added Sveon STV20 device based on Realtek RTL2832U and FC0012 tuner

Signed-off-by: Alessandro Miceli <angelofsky1980@gmail.com>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Cc: stable@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>