package/xz: update license

- Add COPYING to license files as it gives useful info on license
- Add "Public Domain" to XZ_LICENSE (see COPYING)
- Add hash for license files

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/xz/xz.hash

@@ -1,2 +1,8 @@
 # Locally calculated after checking pgp signature
 sha256 fd9ca16de1052aac899ad3495ad20dfa906c27b4a5070102a2ec35ca3a4740c1  xz-5.2.3.tar.bz2
+
+# Hash for license files
+sha256 c4f8e14fafe458d84808a4cd8b69f94673ebe2bf8fc992291629a69ac12218f8  COPYING
+sha256 8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643  COPYING.GPLv2
+sha256 8ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903  COPYING.GPLv3
+sha256 dc626520dcd53a22f727af3ee42c770e56c97a64fe3adb063799d8ab032fe551  COPYING.LGPLv2.1

package/xz/xz.mk

@@ -9,8 +9,8 @@ XZ_SOURCE = xz-$(XZ_VERSION).tar.bz2
 XZ_SITE = http://tukaani.org/xz
 XZ_INSTALL_STAGING = YES
 XZ_CONF_ENV = ac_cv_prog_cc_c99='-std=gnu99'
-XZ_LICENSE = GPL-2.0+, GPL-3.0+, LGPL-2.1+
-XZ_LICENSE_FILES = COPYING.GPLv2 COPYING.GPLv3 COPYING.LGPLv2.1
+XZ_LICENSE = Public Domain, GPL-2.0+, GPL-3.0+, LGPL-2.1+
+XZ_LICENSE_FILES = COPYING COPYING.GPLv2 COPYING.GPLv3 COPYING.LGPLv2.1
 
 ifeq ($(BR2_TOOLCHAIN_HAS_THREADS),y)
 XZ_CONF_OPTS = --enable-threads