Make definition order a bit neater

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/programs/ssl/ssl_test_lib.h b/programs/ssl/ssl_test_lib.h
index d2354bb..e37a9d8 100644
--- a/programs/ssl/ssl_test_lib.h
+++ b/programs/ssl/ssl_test_lib.h
@@ -34,8 +34,8 @@
 #define mbedtls_printf     printf
 #define mbedtls_fprintf    fprintf
 #define mbedtls_snprintf   snprintf
-#define mbedtls_exit            exit
 #define mbedtls_setbuf     setbuf
+#define mbedtls_exit            exit
 #define MBEDTLS_EXIT_SUCCESS    EXIT_SUCCESS
 #define MBEDTLS_EXIT_FAILURE    EXIT_FAILURE
 #endif