net: add the driver-facing netdev_work scheduling API

net: add the driver-facing netdev_work scheduling API

With an extra event mask we can easily extend the netdev work
to also service driver-defined events. For advanced drivers
this is probably not a perfect match, but it makes running
deferred work easier in simple cases.

Expose the netdev_work facility to drivers. Add helpers
to schedule work and a dedicated ndo to perform the driver-
-scheduled actions.

Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20260624182018.2445732-3-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>