Use dummy typedef instead of macro

Use a dummy definition of mbedtls_ms_time_t in builds without
MBEDTLS_HAVE_TIME.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>
diff --git a/tests/suites/test_suite_debug.function b/tests/suites/test_suite_debug.function
index f6d7611..b99e27d 100644
--- a/tests/suites/test_suite_debug.function
+++ b/tests/suites/test_suite_debug.function
@@ -9,13 +9,9 @@
 #   include <crtdbg.h>
 #endif
 
-// Use a macro instead of sizeof(mbedtls_ms_time_t) because the expression store
-// doesn't exclude entries based on depends_on headers, which would cause failures
-// in builds without MBEDTLS_HAVE_TIME
-#if defined(MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO)
-#   define MBEDTLS_MS_TIME_SIZE sizeof(MBEDTLS_PLATFORM_MS_TIME_TYPE_MACRO)
-#else
-#   define MBEDTLS_MS_TIME_SIZE sizeof(int64_t)
+// Dummy type for builds without MBEDTLS_HAVE_TIME
+#if !defined(MBEDTLS_HAVE_TIME)
+typedef int64_t mbedtls_ms_time_t;
 #endif
 
 struct buffer_data {