Fix failing multi-threaded unit test

Signed-off-by: Janos Follath <janos.follath@arm.com>
diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index bdf3dca..0f1237c 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -97,7 +97,7 @@
     memset(out, 0, sizeof(out));
 
     for(int i = 0; i < thread_random_reps; i++) {
-        TEST_EQUAL(mbedtls_ctr_drbg_random_with_add((mbedtls_ctr_drbg_context*) ctx, out, sizeof(out), NULL, 0), 0);
+        TEST_EQUAL(mbedtls_ctr_drbg_random((mbedtls_ctr_drbg_context*) ctx, out, sizeof(out)), 0);
     }
 
 exit: