google/kukui: Update MMU table in romstage and ramstage

In order to get better performance, map dram as cached after dram ready
in romstage.

BUG=b:80501386
BRANCH=none
TEST=Boots correctly on Kukui. Need a futher check after dram
     calibration code ready.

Change-Id: Ie541fe08ee1d5b260abbabc0a5c18fb04e602b9c
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/27304
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/mainboard/google/kukui/mainboard.c b/src/mainboard/google/kukui/mainboard.c
new file mode 100644
index 0000000..212ae80
--- /dev/null
+++ b/src/mainboard/google/kukui/mainboard.c
@@ -0,0 +1,31 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2018 MediaTek Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <device/device.h>
+#include <soc/mmu_operations.h>
+
+static void mainboard_init(struct device *dev)
+{
+}
+
+static void mainboard_enable(struct device *dev)
+{
+	dev->ops->init = &mainboard_init;
+}
+
+struct chip_operations mainboard_ops = {
+	.name = CONFIG_MAINBOARD_PART_NUMBER,
+	.enable_dev = mainboard_enable,
+};