The -e flag to readlink doesn't exist on FreeBSD so change it to -f instead
which is present on both BSD and Linux. Error reported is:
readlink: illegal option -- e
usage: readlink [-fn] [file ...]
usage: dirname string [...]
./devtools/check-git-log.sh: /git-log-fixes.sh: not found
Fixes: 814c8822ef7b ("scripts: check cc stable mailing list in commit")
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>