[NetLabel]: update docs with website information

Now that all of the supporting pieces of NetLabel have a home at SourceForge
update the Kconfig help text and add an entry to the MAINTAINERS file.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netlabel/Kconfig b/net/netlabel/Kconfig
index fe23cb7..9f7121a 100644
--- a/net/netlabel/Kconfig
+++ b/net/netlabel/Kconfig
@@ -9,6 +9,9 @@
 	---help---
 	  NetLabel provides support for explicit network packet labeling
 	  protocols such as CIPSO and RIPSO.  For more information see
-	  Documentation/netlabel.
+	  Documentation/netlabel as well as the NetLabel SourceForge project
+	  for configuration tools and additional documentation.
+
+	   * http://netlabel.sf.net
 
 	  If you are unsure, say N.