mb/google/skywalker: Run MTK FSP binary in ramstage

Load and run mtk_fsp_ramstage.elf in ramstage.

BUG=b:379008996
BRANCH=none
TEST=See coreboot log:
[INFO ]  CBFS: Found 'fallback/mtk_fsp_ramstage' @0x5e8c0 size 0x359
in mcache @0xfffdd298
[INFO ]  _start: MediaTek FSP_RAMSTAGE interface version: 1.0
[INFO ]  [mtk-fsp] RAMSTAGE_SOC_INIT
[INFO ]  _start: status 0
[INFO ]  mtk_fsp_load_and_run: run fallback/mtk_fsp_ramstage at phase
0x50 done

Signed-off-by: Vince Liu <vince-wl.liu@mediatek.corp-partner.google.com>
Change-Id: I1ed5dbeea8fbf08730c5ecc5720b6e1f7677296c
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88124
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/mediatek/mt8189/soc.c

@@ -5,6 +5,7 @@
 #include <soc/dramc_info.h>
 #include <soc/emi.h>
 #include <soc/mcupm.h>
+#include <soc/mtk_fsp.h>
 #include <soc/sspm.h>
 #include <symbols.h>
 
@@ -20,6 +21,9 @@ static void soc_read_resources(struct device *dev)
 
 static void soc_init(struct device *dev)
 {
+	mtk_fsp_init(RAMSTAGE_SOC_INIT);
+	mtk_fsp_load_and_run();
+
 	mcupm_init();
 	sspm_init();
 }