google/kukui: Raise the CPU frequency

Run CPU at the highest freqency (1989MHz) to speed up the boot time.

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

Change-Id: I703ffcb99367f87e6792a72485f5634e0505e5ac
Signed-off-by: Tristan Shieh <tristan.shieh@mediatek.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32466
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.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/pll.h>
 #include <soc/rtc.h>
 
 #include "early_init.h"
@@ -28,6 +29,7 @@ void platform_romstage_main(void)
 		mainboard_early_init();
 
 	mt6358_init();
+	mt_pll_raise_ca53_freq(1989 * MHz);
 	rtc_boot();
 	mt_mem_init(get_sdram_config());
 	mtk_mmu_after_dram();