tools/squashfs4: update to 4.7.2

tools/squashfs4: update to 4.7.2

This minor version update only includes some build fixes and
improvements.

Release Notes:
  https://github.com/plougher/squashfs-tools/releases/tag/4.7.1
  https://github.com/plougher/squashfs-tools/releases/tag/4.7.2

Remove upstream patches:
  001-thread-add-the-missing-pthread.h-header.patch[1]
  002-print_pager-add-missing-includes.patch[2]

[1] https://github.com/plougher/squashfs-tools/commit/b6e9f4b62cc3e762ceeddc0fc099f7d65f7b7361
[2] https://github.com/plougher/squashfs-tools/commit/05a895b3f996d1ac157d95b04980f5f047e7dbf7

Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/19820
Signed-off-by: Nick Hainke <vincent@systemli.org>