V4L/DVB (5702): Fix Kconfig items to avoid linkedition errors

The recent changes on Kconfig broke compilation when VIDEO_DEV is compiled
as module. On some cases, drivers like VIDEO_BUF are compiled with 'y' option
instead of 'm':

...

Thanks to: Toralf Forster <toralf.foerster@gmx.de> for pointing this issue.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/common/Kconfig

@@ -4,5 +4,6 @@ config VIDEO_SAA7146
 
 config VIDEO_SAA7146_VV
 	tristate
+	depends on VIDEO_DEV
 	select VIDEO_BUF
 	select VIDEO_SAA7146

drivers/media/video/Kconfig

@@ -347,7 +347,7 @@ endmenu # encoder / decoder chips
 
 config VIDEO_VIVI
 	tristate "Virtual Video Driver"
-	depends on VIDEO_V4L2 && !SPARC32 && !SPARC64 && PCI
+	depends on VIDEO_V4L2 && !SPARC32 && !SPARC64 && PCI && VIDEO_DEV
 	select VIDEO_BUF
 	default n
 	---help---