V4L/DVB (3932): Convert lnbp21 to a module

Convert lnbp21.h into a linux kernel module.
Fix up previous users to use it.
Convert dvb-ttusb-budget to use it.

Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/dvb/frontends/Kconfig b/drivers/media/dvb/frontends/Kconfig
index 6d90ff3..64cd636 100644
--- a/drivers/media/dvb/frontends/Kconfig
+++ b/drivers/media/dvb/frontends/Kconfig
@@ -216,4 +216,14 @@
 	  An ATSC 8VSB and QAM64/256 tuner module. Say Y when you want
 	  to support this frontend.
 
+
+comment "Miscellaneous devices"
+	depends on DVB_CORE
+
+config DVB_LNBP21
+	tristate "LNBP21 SEC controller"
+	depends on DVB_CORE
+	help
+	  An SEC control chip.
+
 endmenu