Merge branch 'net-ethtool-introduce-ethnl-dump-helpers'

Maxime Chevallier says:

====================
net: ethtool: Introduce ethnl dump helpers

This is V8 for per-phy DUMP helpers, improving support for ->dumpit()
operations for PHY targetting commands.

This V8 fixes some issues spotted by Jakub (thanks !) on the multi-part
DUMP sequence. The netdev reftracking was reworked to make sure that
during a filtered DUMP, we only keep a ref on the netdev during
individual .dumpit() calls.

v1: https://lore.kernel.org/20250305141938.319282-1-maxime.chevallier@bootlin.com
v2: https://lore.kernel.org/20250308155440.267782-1-maxime.chevallier@bootlin.com
v3: https://lore.kernel.org/20250313182647.250007-1-maxime.chevallier@bootlin.com
v4: https://lore.kernel.org/20250324104012.367366-1-maxime.chevallier@bootlin.com
v5: https://lore.kernel.org/20250410123350.174105-1-maxime.chevallier@bootlin.com
v6: https://lore.kernel.org/20250415085155.132963-1-maxime.chevallier@bootlin.com
v7: https://lore.kernel.org/20250422161717.164440-1-maxime.chevallier@bootlin.com
====================

Link: https://patch.msgid.link/20250502085242.248645-1-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>