V4L/DVB (3495): Kconfig: select VIDEO_CX25840 to build cx25840 a/v decoder module

The cx25840 module requires external firmware in order to function,
so it must select FW_LOADER, but saa7115 and saa7129 do not require it.
This patch creates VIDEO_CX25840, and alters VIDEO_DECODER to select it.

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index 87b1ce6..c15f849 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -62,6 +62,7 @@
 
 obj-$(CONFIG_VIDEO_M32R_AR_M64278) += arv.o
 
-obj-$(CONFIG_VIDEO_DECODER)     += saa7115.o cx25840/ saa7127.o
+obj-$(CONFIG_VIDEO_DECODER)     += saa7115.o saa7127.o
+obj-$(CONFIG_VIDEO_CX25840) += cx25840/
 
 EXTRA_CFLAGS += -I$(srctree)/drivers/media/dvb/dvb-core