[media] ds3000: fix reading array out of bound in ds3000_read_snr

An attempt was made to read dvbs2_snr_tab[80],
though dvbs2_snr_tab has only 80 elements.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/dvb-frontends/ds3000.c

@@ -616,7 +616,7 @@ static int ds3000_read_snr(struct dvb_frontend *fe, u16 *snr)
 			snr_reading = dvbs2_noise_reading / tmp;
 			if (snr_reading > 80)
 				snr_reading = 80;
-			*snr = -(dvbs2_snr_tab[snr_reading] / 1000);
+			*snr = -(dvbs2_snr_tab[snr_reading - 1] / 1000);
 		}
 		dprintk("%s: raw / cooked = 0x%02x / 0x%04x\n", __func__,
 				snr_reading, *snr);