mb/google/corsola: Initialize MT6315 for MT8186T

Initialize MT6315 for powering on big cores on MT8186T.

BUG=b:249436110
TEST=build pass.
BRANCH=corsola

Signed-off-by: Sen Chu <sen.chu@mediatek.corp-partner.google.com>
Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
Change-Id: Ib1d71d4f1689ba1e7ea5f798503ef11eff423fff
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68621
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Yidi Lin <yidilin@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/corsola/romstage.c

@@ -3,9 +3,12 @@
 #include <arch/stages.h>
 #include <console/console.h>
 #include <delay.h>
+#include <soc/cpu_id.h>
 #include <soc/emi.h>
+#include <soc/mt6315.h>
 #include <soc/mt6366.h>
 #include <soc/pll_common.h>
+#include <soc/pmif.h>
 #include <soc/regulator.h>
 #include <soc/rtc.h>
 
@@ -27,5 +30,11 @@ void platform_romstage_main(void)
 	mt6366_init();
 	raise_little_cpu_freq();
 	rtc_boot();
+
+	if (get_cpu_id() == MTK_CPU_ID_MT8186T) {
+		mtk_pmif_init();
+		mt6315_init();
+	}
+
 	mtk_dram_init();
 }