Revert "tools/xz: update to 5.6.1" (CVE-2024-3094)

This reverts commit 714c91d1a63f29650abaa9cf69ffa47cf2c70297 as probably
the upstream xz repository and the xz tarballs have been backdoored.

References: https://www.openwall.com/lists/oss-security/2024/03/29/4.
Signed-off-by: Petr Štetiar <[email protected]>

tools/xz/Makefile

@@ -7,11 +7,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=xz
-PKG_VERSION:=5.6.1
+PKG_VERSION:=5.4.6
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
-PKG_SOURCE_URL:=https://github.com/tukaani-project/xz/releases/download/v$(PKG_VERSION)
-PKG_HASH:=d300422649a0124b1121630be559c890ceedf32667d7064b8128933166c217c8
+PKG_SOURCE_URL:=@SF/lzmautils \
+		http://tukaani.org/xz
+PKG_HASH:=913851b274e8e1d31781ec949f1c23e8dbcf0ecf6e73a2436dc21769dd3e6f49
 PKG_CPE_ID:=cpe:/a:tukaani:xz
 
 HOST_BUILD_PARALLEL:=1