mb/google/myst/bootblock.c: Initialize spi flash

Initialize the SPI Flash in bootblock to ensure that
CONFIG_SPI_FLASH_EXIT_4_BYTE_ADDR_MODE will exit 4-byte addressing mode.

BUG=b:285110121
TEST=boot myst and verify flash operations work correctly

Change-Id: Ia88d2b46884b096b4c558bc86513159ec6d35eb5
Signed-off-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75588
Reviewed-by: Jon Murphy <jpmurphy@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/myst/bootblock.c

@@ -3,7 +3,9 @@
 #include <amdblocks/espi.h>
 #include <bootblock_common.h>
 #include <baseboard/variants.h>
+#include <console/console.h>
 #include <soc/espi.h>
+#include <spi_flash.h>
 
 void mb_set_up_early_espi(void)
 {
@@ -35,4 +37,8 @@ void bootblock_mainboard_init(void)
 
 	variant_bootblock_gpio_table(&gpios, &num_gpios);
 	gpio_configure_pads(gpios, num_gpios);
+
+	// TODO: b:285110121 - temp workaround is to add a dummy flash call
+	const struct spi_flash *spi = boot_device_spi_flash();
+	printk(BIOS_DEBUG, "Initialized spi flash %p\n", spi);
 }