[media] it913x-fe ver 1.15 read signal strenght using reg VAR_P_INBAND

Read signal strength using VAR_P_INBAND and apply FEC preferred values.

Note this does not work on IT9137 devices even with dvb-usb-it9135-01.fw
firmware.

Config read_sl allows switch between read signal strength and signal
level.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/dvb-usb/it913x.c b/drivers/media/dvb/dvb-usb/it913x.c
index cfa415b..3b7b102 100644
--- a/drivers/media/dvb/dvb-usb/it913x.c
+++ b/drivers/media/dvb/dvb-usb/it913x.c
@@ -412,11 +412,13 @@
 	case IT9135_V1_FW:
 		it913x_config.firmware_ver = 1;
 		it913x_config.adc_x2 = 1;
+		it913x_config.read_slevel = false;
 		props->firmware = fw_it9135_v1;
 		break;
 	case IT9135_V2_FW:
 		it913x_config.firmware_ver = 1;
 		it913x_config.adc_x2 = 1;
+		it913x_config.read_slevel = false;
 		props->firmware = fw_it9135_v2;
 		switch (it913x_config.tuner_id_0) {
 		case IT9135_61:
@@ -432,6 +434,7 @@
 	default:
 		it913x_config.firmware_ver = 0;
 		it913x_config.adc_x2 = 0;
+		it913x_config.read_slevel = true;
 		props->firmware = fw_it9137;
 	}