[NetLabel]: tie NetLabel into the Kconfig system

Modify the net/Kconfig file to enable selecting the NetLabel Kconfig
options.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/Kconfig b/net/Kconfig
index 4959a4e..eb855b7 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -249,6 +249,8 @@
 config WIRELESS_EXT
 	bool
 
+source "net/netlabel/Kconfig"
+
 endif   # if NET
 endmenu # Networking