ssl_helper: fix missin initialization of cli_log_obj

Signed-off-by: Pengyu Lv <pengyu.lv@arm.com>
diff --git a/tests/src/test_helpers/ssl_helpers.c b/tests/src/test_helpers/ssl_helpers.c
index 4527885..1390b7a 100644
--- a/tests/src/test_helpers/ssl_helpers.c
+++ b/tests/src/test_helpers/ssl_helpers.c
@@ -73,7 +73,7 @@
     opts->renegotiate = 0;
     opts->legacy_renegotiation = MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION;
     opts->srv_log_obj = NULL;
-    opts->srv_log_obj = NULL;
+    opts->cli_log_obj = NULL;
     opts->srv_log_fun = NULL;
     opts->cli_log_fun = NULL;
     opts->resize_buffers = 1;