Merge branch 'tools-net-ynl-rework-async-notification-handling'

Donald Hunter says:

====================
tools/net/ynl: rework async notification handling

Revert patch 1bf70e6c3a53 which modified check_ntf() and instead add a
new poll_ntf() with async notification semantics. See patch 2 for a
detailed description.
====================

Link: https://patch.msgid.link/20241113090843.72917-1-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>