[packages] squashfs-tools: update Makefile

git-svn-id: svn://svn.openwrt.org/openwrt@36372 3c298f89-4303-0410-b956-a3cf2f4a3e73
[packages] xz: update Makefile

git-svn-id: svn://svn.openwrt.org/openwrt@36373 3c298f89-4303-0410-b956-a3cf2f4a3e73