chrony: fix build failure due to missing inclusion of util.h

chrony: fix build failure due to missing inclusion of util.h

During build package stops with linker error:
hash_intmd5.o: In function `HSH_Hash':
hash_intmd5.c:(.text+0x963): undefined reference to `MIN'

This is due to missing util.h inclusion.
util.h contains MIN() macro definition.

Add upstream patch:
https://git.tuxfamily.org/chrony/chrony.git/commit/?id=948ecf84314f78da82e0e2b07b6570ca9cff86c8
to add #include "util.h" in hash_intmd5.c

Fixes:
http://autobuild.buildroot.net/results/8f0/8f0d53b1d5a899e56540c859b908cbc1eaa223d5/
http://autobuild.buildroot.net/results/3c6/3c609f94aff182c9ab47ef8ec4b9de03a4d20ffb/
http://autobuild.buildroot.net/results/f1f/f1fcae399fb640c19cf88c9333a92cbfab547932/

Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>