Merge: selftests/net: enable mptcp in testing netns

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/407

JIRA: https://issues.redhat.com/browse/RHEL-80379

Upstream Status: net-next.git commit 0f58804

Signed-off-by: Hangbin Liu <haliu@redhat.com>

Approved-by: Davide Caratti <dcaratti@redhat.com>
Approved-by: Florian Westphal <fwestpha@redhat.com>

Merged-by: Julio Faracco <jfaracco@redhat.com>

Author: jcfaracco

tools/testing/selftests/net/ip_local_port_range.sh

@@ -2,4 +2,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
 ./in_netns.sh \
-  sh -c 'sysctl -q -w net.ipv4.ip_local_port_range="40000 49999" && ./ip_local_port_range'
+  sh -c 'sysctl -q -w net.mptcp.enabled=1 && \
+         sysctl -q -w net.ipv4.ip_local_port_range="40000 49999" && \
+         ./ip_local_port_range'