[media] af9013: fix AF9013 TDA18271 IF config

IF freq	for DVB-T 7 MHz	and 8 MHz was set slightly wrong. Due to that it
didn't worked at all (?) for 7 MHz channels and most likely performance
was dropped for 8 MHz channels.

That bug was pointed by few people during last two months. Thank you.

Trivial fix. Compile tested only due to lack of proper HW and signal.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Cc: Romolo Manfredini <romoloman@hotmail.com>
Cc: Alireza Moini <alireza.moini@silverbrookresearch.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/af9013.c

@@ -334,11 +334,11 @@ static int af9013_set_freq_ctrl(struct af9013_state *state, fe_bandwidth_t bw)
 				if_sample_freq = 3300000; /* 3.3 MHz */
 				break;
 			case BANDWIDTH_7_MHZ:
-				if_sample_freq = 3800000; /* 3.8 MHz */
+				if_sample_freq = 3500000; /* 3.5 MHz */
 				break;
 			case BANDWIDTH_8_MHZ:
 			default:
-				if_sample_freq = 4300000; /* 4.3 MHz */
+				if_sample_freq = 4000000; /* 4.0 MHz */
 				break;
 			}
 		} else if (state->config.tuner == AF9013_TUNER_TDA18218) {