Merge branch 'mptcp-add-last-time-fields-in-mptcp_info'

Matthieu Baerts says:

====================
mptcp: add last time fields in mptcp_info

These patches from Geliang add support for the "last time" field in
MPTCP Info, and verify that the counters look valid.

Patch 1 adds these counters: last_data_sent, last_data_recv and
last_ack_recv. They are available in the MPTCP Info, so exposed via
getsockopt(MPTCP_INFO) and the Netlink Diag interface.

Patch 2 adds a test in diag.sh MPTCP selftest, to check that the
counters have moved by at least 250ms, after having waited twice that
time.

v1: https://lore.kernel.org/r/20240405-upstream-net-next-20240405-mptcp-last-time-info-v1-0-52dc49453649@kernel.org
====================

Link: https://lore.kernel.org/r/20240410-upstream-net-next-20240405-mptcp-last-time-info-v2-0-f95bd6b33e51@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>