[media] rtl28xxu: add [1b80:d3b0] Sveon STV21

Added Sveon STV21 device based on Realtek RTL2832U and FC0013 tuner

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>
Acked-by: Antti Palosaari <crope@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>