ethtool: linkstate: fix unbalanced ethnl_ops_complete() on PHY lookup error

ethtool: linkstate: fix unbalanced ethnl_ops_complete() on PHY lookup error

linkstate_prepare_data() calls ethnl_req_get_phydev() before
ethnl_ops_begin(), but routes its error path through "goto out"
which calls ethnl_ops_complete().

Fixes: fe55b1d401c6 ("ethtool: linkstate: migrate linkstate functions to support multi-PHY setups")
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260526153533.2779187-4-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>