google/kukui: Add RTC initialization

Initialize RTC at ROM stage.

BUG=b:80501386
BRANCH=none
TEST=Boots correctly on Kukui

Change-Id: I9d9c68755e8a6ac65dd794211e6ccf06e5057567
Signed-off-by: Ran Bi <ran.bi@mediatek.com>
Reviewed-on: https://review.coreboot.org/c/31508
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

src/mainboard/google/kukui/romstage.c

@@ -17,6 +17,7 @@
 #include <soc/emi.h>
 #include <soc/mmu_operations.h>
 #include <soc/mt6358.h>
+#include <soc/rtc.h>
 
 #include "early_init.h"
 
@@ -27,6 +28,7 @@ void platform_romstage_main(void)
 		mainboard_early_init();
 
 	mt6358_init();
+	rtc_boot();
 	mt_mem_init(get_sdram_config());
 	mtk_mmu_after_dram();
 }