net: pse-pd: Use EOPNOTSUPP error code instead of ENOTSUPP

net: pse-pd: Use EOPNOTSUPP error code instead of ENOTSUPP

BugLink: https://bugs.launchpad.net/bugs/2074091
[ Upstream commit 144ba8580bcb82b2686c3d1a043299d844b9a682 ]

ENOTSUPP is not a SUSV4 error code, prefer EOPNOTSUPP as reported by
checkpatch script.

Fixes: 18ff0bcda6d1 ("ethtool: add interface to interact with Ethernet Power Equipment")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240610083426.740660-1-kory.maincent@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Portia Stephens <portia.stephens@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>