Since upstream commit [1] ("Deprecate the slaveOnly option in favor
of clientOnly."), included in v4.0, ptp4l complains about the
"slaveOnly" option being deprecated on startup.
Update the default config to silence this warning.
[1] fe01cc7c96
Signed-off-by: Florian Larysch <fl@n621.de>
Signed-off-by: Julien Olivain <ju.o@free.fr>
(cherry picked from commit f70b83914f)
Signed-off-by: Titouan Christophe <titouan.christophe@mind.be>