libxtst: fix metadata

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>

meta/packages/xorg-lib/libxtst_1.1.0.bb

@@ -1,6 +1,11 @@
 require xorg-lib-common.inc
 
 DESCRIPTION = "X Test Extension: client side library"
+
+LICENSE = "MIT-style"
+LIC_FILES_CHKSUM = "file://COPYING;md5=cba677ca25c42ad29ee8ff351b50ece8 \
+                    file://src/XTest.c;beginline=2;endline=32;md5=1491d278aeb574e84c5235eb44cdac74"
+
 DEPENDS += "libxext recordproto inputproto libxi"
 PROVIDES = "xtst"
 PR = "r2"