util-linux: re-add <pkg>_AUTORECONF = YES

Commit a5015f10 ("util-linux: security
bump to version 2.29.2") incorrectly removed <pkg>_AUTORECONF = YES.

While the patches touching configure.ac have indeed been removed, there
is still a patch touching a Makemodule.am file, which triggers an
autoreconf a build time, which itself fails because autoconf/automake
are not available.

So re-add <pkg>_AUTORECONF, with a comment pointing specifically at the
patch that makes it necessary.

Fixes:

  http://autobuild.buildroot.net/results/309127a532eed00e406bbaf0b1a51b7241a10505/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>