[media] dvb: frontend.h: add a note for the deprecated enums/structs

Let be clear, at the header, about what got deprecated.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/include/uapi/linux/dvb/frontend.h b/include/uapi/linux/dvb/frontend.h
index e764fd8..00a20cd 100644
--- a/include/uapi/linux/dvb/frontend.h
+++ b/include/uapi/linux/dvb/frontend.h
@@ -486,6 +486,12 @@
 
 #if defined(__DVB_CORE__) || !defined (__KERNEL__)
 
+/*
+ * DEPRECATED: The DVBv3 ioctls, structs and enums should not be used on
+ * newer programs, as it doesn't support the second generation of digital
+ * TV standards, nor supports newer delivery systems.
+ */
+
 enum fe_bandwidth {
 	BANDWIDTH_8_MHZ,
 	BANDWIDTH_7_MHZ,