selftests: mptcp: connect: fix fallback note due to OoO

selftests: mptcp: connect: fix fallback note due to OoO

The "fallback due to TCP OoO" was never printed because the stat_ooo_now
variable was checked twice: once in the parent if-statement, and one in
the child one. The second condition was then always true then, and the
'else' branch was never taken.

The idea is that when there are more ACK + MP_CAPABLE than expected, the
test either fails if there was no out of order packets, or a notice is
printed.

Fixes: 69ca3d29a755 ("mptcp: update selftest for fallback due to OoO")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251110-net-mptcp-sft-join-unstable-v1-1-a4332c714e10@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>