[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/frontends/it913x-fe.h b/drivers/media/dvb/frontends/it913x-fe.h
index c4a908e..07fa459 100644
--- a/drivers/media/dvb/frontends/it913x-fe.h
+++ b/drivers/media/dvb/frontends/it913x-fe.h
@@ -34,6 +34,8 @@
 	u8 tuner_id_1;
 	u8 dual_mode;
 	u8 adf;
+	/* option to read SIGNAL_LEVEL */
+	u8 read_slevel;
 };
 
 #if defined(CONFIG_DVB_IT913X_FE) || (defined(CONFIG_DVB_IT913X_FE_MODULE) && \
@@ -168,6 +170,8 @@
 #define EST_SIGNAL_LEVEL	0x004a
 #define FREE_BAND		0x004b
 #define SUSPEND_FLAG		0x004c
+#define VAR_P_INBAND		0x00f7
+
 /* Build in tuner types */
 #define IT9137 0x38
 #define IT9135_38 0x38