net: ethtool: tsconfig: set command must provide a reply

Timestamping configuration through ethtool has inconsistent behavior of
skipping the reply for set command if configuration was not changed. Fix
it be providing reply in any case.

Fixes: 6e9e2eed ("net: ethtool: Add support for tsconfig command to get/set hwtstamp config")
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20250922231924.2769571-1-vadfed@meta.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>