tools/testing/selftests/bpf/test_tc_tunnel.sh: Fix wait for server bind

Commit f803bcf ("selftests/bpf: Prevent client connect before
server bind in test_tc_tunnel.sh") added code that waits for the
netcat server to start before the netcat client attempts to connect to
it. However, not all calls to 'server_listen' were guarded.

This patch adds the existing 'wait_for_port' guard after the remaining
call to 'server_listen'.

Fixes: f803bcf ("selftests/bpf: Prevent client connect before server bind in test_tc_tunnel.sh")
Signed-off-by: Marco Leogrande <[email protected]>

tools/testing/selftests/bpf/test_tc_tunnel.sh

@@ -305,6 +305,7 @@ else
 	client_connect
 	verify_data
 	server_listen
+	wait_for_port ${port} ${netcat_opt}
 fi
 
 # serverside, use BPF for decap