luaexpat: add LICENSE_FILES

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/luaexpat/luaexpat.mk

@@ -7,5 +7,6 @@
 LUAEXPAT_VERSION = 1.3.0-1
 LUAEXPAT_DEPENDENCIES = expat
 LUAEXPAT_LICENSE = MIT
+LUAEXPAT_LICENSE_FILES = $(LUAEXPAT_SUBDIR)/doc/us/license.html
 
 $(eval $(luarocks-package))