Merge branch 'net-ethtool-rss-add-notifications'

Jakub Kicinski says:

====================
net: ethtool: rss: add notifications

Next step on the path to moving RSS config to Netlink. With the
refactoring of the driver-facing API for ETHTOOL_GRXFH/ETHTOOL_SRXFH
out of the way we can move on to more interesting work.

Add Netlink notifications for changes in RSS configuration.

As a reminder (part) of rss-get was introduced in previous releases
when input-xfrm (symmetric hashing) was added. rss-set isn't
implemented, yet, but we can implement rss-ntf and hook it into
the changes done via the IOCTL path (same as other ethtool-nl
notifications do).

Most of the series is concerned with passing arguments to notifications.
So far none of the notifications needed to be parametrized, but RSS can
have multiple contexts per device, and since GET operates on a single
context at a time, the notification needs to also be scoped to a context.
Patches 2-5 add support for passing arguments to notifications thru
ethtool-nl generic infra.

The notification handling itself is pretty trivial, it's mostly
hooking in the right entries into the ethool-nl op tables.

v1: https://lore.kernel.org/20250621171944.2619249-1-kuba@kernel.org
====================

Link: https://patch.msgid.link/20250623231720.3124717-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>