Add package license information

Signed-off-by: Jonathan Bennett <jbennett@incomsystems.biz>

net/fwknop/Makefile

@@ -15,6 +15,7 @@ PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=http://www.cipherdyne.org/fwknop/download
 PKG_MD5SUM:=1ae000a499bf604a2aeef4d0a7a178c8
 PKG_MAINTAINER:=Jonathan Bennett <JBennett@incomsystems.biz>
+PKG_LICENSE:=GPLv2
 PKG_INSTALL:=1
 
 include $(INCLUDE_DIR)/package.mk