radsecproxy: Update copyright notice, add license

Signed-off-by: Ondřej Caletka <ondrej@caletka.cz>

net/radsecproxy/Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (C) 2008-2012 OpenWrt.org
+# Copyright (C) 2008-2016 OpenWrt.org
 #
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
@@ -15,6 +15,9 @@ PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=http://software.uninett.no/radsecproxy/
 PKG_MD5SUM:=d76cf4fc68515667b8c67387f5045150
 
+PKG_LICENSE:=GPL-2.0+
+PKG_LICENSE_FILES:=LICENSE
+
 PKG_INSTALL:=1
 
 include $(INCLUDE_DIR)/package.mk