Merge branch 'mptcp-misc-fixes-for-6-15-rc0'

Matthieu Baerts says:

====================
mptcp: misc. fixes for 6.15-rc0

Here are 4 unrelated patches:

- Patch 1: fix a NULL pointer when two SYN-ACK for the same request are
  handled in parallel. A fix for up to v5.9.

- Patch 2: selftests: fix check for the wrong FD. A fix for up to v5.17.

- Patch 3: selftests: close all FDs in case of error. A fix for up to
  v5.17.

- Patch 4: selftests: ignore a new generated file. A fix for 6.15-rc0.
====================

Link: https://patch.msgid.link/20250328-net-mptcp-misc-fixes-6-15-v1-0-34161a482a7f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>