net: make CONFIG_NETLABEL explicitly dependent on CONFIG_INET

This should resolve an issue found during testing with random configuration files.

net/built-in.o: In function `netlbl_cfg_cipsov4_add':
(.text+0x61757): undefined reference to cipso_v4_doi_add' net/built-in.o: In function netlbl_cfg_cipsov4_del':
(.text+0x6177d): undefined reference to `cipso_v4_doi_remove' [... and so on ...]

---
 net/netlabel/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 56958c8..f272826 100644
@@ -4,7 +4,7 @@
 
 config NETLABEL
 	bool "NetLabel subsystem support"
-	depends on SECURITY
+	depends on SECURITY && INET
 	default n
 	---help---
 	  NetLabel provides support for explicit network packet labeling