xmlstarlet: add license information

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Arnout Vandecappelle <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/xmlstarlet/xmlstarlet.mk

@@ -6,6 +6,8 @@
 
 XMLSTARLET_VERSION = 1.3.0
 XMLSTARLET_SITE = http://downloads.sourceforge.net/project/xmlstar/xmlstarlet/$(XMLSTARLET_VERSION)
+XMLSTARLET_LICENSE = MIT
+XMLSTARLET_LICENSE_FILES = COPYING
 
 XMLSTARLET_DEPENDENCIES += libxml2 libxslt \
 	$(if $(BR2_PACKAGE_LIBICONV),libiconv)