stress-ng: update to 0.06.02
Fixes following autobuilder errors:
http://autobuild.buildroot.net/results/b527ccdbdfeaba6789528e68df93d9c7216e758a/
http://autobuild.buildroot.net/results/d658f82c66d93515276dcb6cec8d3690459fbf05/
Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>