V4L/DVB (13160): DocBook/Makefile: add linux/dvb/frontend.h header file

Adds linux/dvb/frontend.h header file at DocBook, and creates cross-references
for the frontend ioctls.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/dvb/dvbapi.xml

@@ -85,3 +85,8 @@ Added ISDB-T test originally written by Patrick Boettcher
     &sub-examples;
   </chapter>
 <!-- END OF CHAPTERS -->
+  <appendix id="frontend_h">
+    <title>DVB Frontend Header File</title>
+    &sub-frontend-h;
+  </appendix>
+

Documentation/DocBook/media-entities.tmpl

@@ -288,6 +288,7 @@
 <!ENTITY sub-net SYSTEM "dvb/net.xml">
 <!ENTITY sub-kdapi SYSTEM "dvb/kdapi.xml">
 <!ENTITY sub-examples SYSTEM "dvb/examples.xml">
+<!ENTITY sub-frontend-h SYSTEM "dvb/frontend.h.xml">
 <!ENTITY sub-dvbapi SYSTEM "dvb/dvbapi.xml">
 <!ENTITY sub-media SYSTEM "media.xml">
 <!ENTITY sub-media-entities SYSTEM "media-entities.tmpl">