tcpreplay: add PKG_LICENSE_FILES

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

net/tcpreplay/Makefile

@@ -9,13 +9,14 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=tcpreplay
 PKG_VERSION:=4.1.1
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://github.com/appneta/tcpreplay/releases/download/v$(PKG_VERSION)
 PKG_MD5SUM:=80394c33fe697b53b69eac9bb0968ae9
 
 PKG_LICENSE:=GPL-3.0
+PKG_LICENSE_FILES:=docs/LICENSE
 
 PKG_FIXUP:=libtool
 PKG_INSTALL:=1