[PATCH 6.1.y] selftests: mptcp: join: fix dev in check_endpoint

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

From: Geliang Tang <tanggeliang@kylinos.cn>

There's a bug in pm_nl_check_endpoint(), 'dev' didn't be parsed correctly.
If calling it in the 2nd test of endpoint_tests() too, it fails with an
error like this:

 creation  [FAIL] expected '10.0.2.2 id 2 subflow dev dev' \
                     found '10.0.2.2 id 2 subflow dev ns2eth2'

The reason is '$2' should be set to 'dev', not '$1'. This patch fixes it.

Fixes: 69c6ce7b6eca ("selftests: mptcp: add implicit endpoint test case")
Cc: stable@vger.kernel.org
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240329-upstream-net-20240329-fallback-mib-v1-2-324a8981da48@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit 40061817d95bce6dd5634a61a65cd5922e6ccc92)
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Notes:
  - Conflicts in mptcp_join.sh: only the fix has been added, not the
    verification because this modified subtest is quite different in
    v6.1: to add this verification, we would need to change a bit the
    subtest: pm_nl_check_endpoint() takes an extra argument for the
    title, the next chk_subflow_nr() will no longer need the title, etc.
    Easier with only the fix without the extra test.
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index a20dca9d26d6..0b433606a298 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -725,7 +725,7 @@ pm_nl_check_endpoint()
 			[ -n "$_flags" ]; flags="flags $_flags"
 			shift
 		elif [ $1 = "dev" ]; then
-			[ -n "$2" ]; dev="dev $1"
+			[ -n "$2" ]; dev="dev $2"
 			shift
 		elif [ $1 = "id" ]; then
 			_id=$2
-- 
2.43.0