mb/google/corsola: Add NOR-Flash support

Add NOR-Flash drivers to pass verification of flash at verstage.

TEST=boot to romstage
BUG=b:202871018

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Change-Id: Iee3dd336632b0cf998f5f7c1d118e01e8270e815
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58838
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>

src/mainboard/google/corsola/Kconfig

@@ -22,4 +22,8 @@ config MAINBOARD_DIR
 config MAINBOARD_PART_NUMBER
 	string
 	default "Corsola" if BOARD_GOOGLE_CORSOLA
+
+config BOOT_DEVICE_SPI_FLASH_BUS
+	int
+	default 7
 endif

src/mainboard/google/corsola/bootblock.c

@@ -2,7 +2,9 @@
 
 #include <bootblock_common.h>
 #include <device/mmio.h>
+#include <soc/spi.h>
 
 void bootblock_mainboard_init(void)
 {
+	mtk_snfc_init(SPI_NOR_GPIO_SET0);
 }