lua: Add license info

Signed-off-by: Danomi Manchego <danomimanchego123@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Luca Ceresoli <luca@lucaceresoli.net>

package/lua/lua.mk

@@ -7,6 +7,8 @@
 LUA_VERSION = 5.1.5
 LUA_SITE = http://www.lua.org/ftp
 LUA_INSTALL_STAGING = YES
+LUA_LICENSE = MIT
+LUA_LICENSE_FILES = COPYRIGHT
 
 LUA_CFLAGS = -Wall
 ifeq ($(BR2_PACKAGE_LUA_SHARED_LIBRARY),y)