Merge branch 'mptcp-more-fixes-for-6-5'

Mat Martineau says:

====================
mptcp: More fixes for 6.5

Patch 1: Better detection of ip6tables vs ip6tables-legacy tools for
self tests. Fix for 6.4 and newer.

Patch 2: Only generate "new listener" event if listen operation
succeeds. Fix for 6.2 and newer.
====================

Link: https://lore.kernel.org/r/20230725-send-net-20230725-v1-0-6f60fe7137a9@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>