Ensure mutex test mutex gets free'd

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index d8ff49e..cc28697 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -772,6 +772,10 @@
     mbedtls_fprintf(stdout, " (%u / %u tests (%u skipped))\n",
                     total_tests - total_errors, total_tests, total_skipped);
 
+#if defined(MBEDTLS_TEST_MUTEX_USAGE)
+    mbedtls_test_mutex_usage_end();
+#endif
+
 #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) && \
     !defined(TEST_SUITE_MEMORY_BUFFER_ALLOC)
 #if defined(MBEDTLS_MEMORY_DEBUG)