tools: util-linux: update to v2.40.2

tools: util-linux: update to v2.40.2

Also switch from .tar.gz to .tar.xz to align with
package/utils/util-linux/Makefile.
This makes synchronized updates easier.

Release Notes:
        https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.40/v2.40-ReleaseNotes
        https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.40/v2.40.1-ReleaseNotes
        https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.40/v2.40.2-ReleaseNotes

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
Link: https://github.com/openwrt/openwrt/pull/15995
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>