[media] saa7134: Fix compilation breakage when go7007 is not selected

All error/warnings:

   drivers/built-in.o: In function `saa7134_go7007_fini':
>> saa7134-go7007.c:(.text+0x3b628b): undefined reference to `go7007_snd_remove'
   drivers/built-in.o: In function `saa7134_go7007_interface_reset':
>> saa7134-go7007.c:(.text+0x3b659a): undefined reference to `go7007_read_interrupt'
   drivers/built-in.o: In function `saa7134_go7007_init':
>> saa7134-go7007.c:(.text+0x3b65fa): undefined reference to `go7007_alloc'
>> saa7134-go7007.c:(.text+0x3b66ed): undefined reference to `go7007_boot_encoder'
>> saa7134-go7007.c:(.text+0x3b66fe): undefined reference to `go7007_register_encoder'
   drivers/built-in.o: In function `saa7134_go7007_irq_ts_done':
>> saa7134-go7007.c:(.text+0x3b6c2a): undefined reference to `go7007_parse_video_stream'
>> saa7134-go7007.c:(.text+0x3b6c86): undefined reference to `go7007_parse_video_stream'

This happens when:
 - VIDEO_SAA7134 is either 'm' or 'y'
 - VIDEO_GO7007 is not selected.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/pci/saa7134/Kconfig

@@ -63,3 +63,11 @@ config VIDEO_SAA7134_DVB
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called saa7134-dvb.
+
+config VIDEO_SAA7134_GO7007
+	tristate "go7007 support for saa7134 based TV cards"
+	depends on VIDEO_SAA7134
+	depends on VIDEO_GO7007
+	---help---
+	  Enables saa7134 driver support for boards with go7007
+	  MPEG encoder (WIS Voyager or compatible).

drivers/media/pci/saa7134/Makefile

@@ -4,7 +4,8 @@ saa7134-y +=	saa7134-ts.o saa7134-tvaudio.o saa7134-vbi.o
 saa7134-y +=	saa7134-video.o
 saa7134-$(CONFIG_VIDEO_SAA7134_RC) += saa7134-input.o
 
-obj-$(CONFIG_VIDEO_SAA7134) +=  saa7134.o saa7134-empress.o saa7134-go7007.o
+obj-$(CONFIG_VIDEO_SAA7134) +=  saa7134.o saa7134-empress.o
+obj-$(CONFIG_VIDEO_SAA7134_GO7007) += saa7134-go7007.o
 
 obj-$(CONFIG_VIDEO_SAA7134_ALSA) += saa7134-alsa.o