Getting this to work required fixing a small issue in `lfs2_util.h`, which
has been submitted upstream.
Signed-off-by: Daniël van de Giessen <daniel@dvdgiessen.nl>
Going above the root directory (/../foo) now gives an error. This is an
intentional change made by LittleFS. It required a update of the testsuite
and is a (minor) compatibility break.
Signed-off-by: Daniël van de Giessen <daniel@dvdgiessen.nl>
