wavemon: Add PKG_LICENSE information

Signed-off-by: Jonathan McCrohan <jmccrohan@gmail.com>

net/wavemon/Makefile

@@ -14,6 +14,8 @@ PKG_RELEASE:=1
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
 PKG_SOURCE_URL:=http://eden-feed.erg.abdn.ac.uk/wavemon/stable-releases
 PKG_MD5SUM:=c60e25feb8b1785cf14371556f0613f4
+PKG_LICENSE:=GPL-2.0+
+PKG_LICENSE_FILES:=COPYING
 
 PKG_INSTALL:=1