soc/amd/stoneyridge: Enable CMOS VBNV backup to flash

Now that we have SPI flash writes working, we can support
VBOOT_VBNV_CMOS_BACKUP_TO_FLASH. This requires the mainboard to reserve
the area in FMAP.

BUG=b:77347873
TEST=Manually clear CMOS and check coreboot restores VBNV from flash.

Change-Id: I488dbfc4c200f5100374d47feb0a0522e6a60e88
Signed-off-by: Marc Jones <marc.jones@scarletltd.com>
Reviewed-on: https://review.coreboot.org/25842
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/stoneyridge/Kconfig

@@ -55,6 +55,7 @@ config CPU_SPECIFIC_OPTIONS
 	select C_ENVIRONMENT_BOOTBLOCK
 	select BOOTBLOCK_CONSOLE
 	select BOOT_DEVICE_SUPPORTS_WRITES if BOOT_DEVICE_SPI_FLASH
+	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
 	select RELOCATABLE_MODULES
 	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM
 	select PARALLEL_MP
@@ -72,6 +73,8 @@ config VBOOT
 	select VBOOT_SEPARATE_VERSTAGE
 	select VBOOT_STARTS_IN_BOOTBLOCK
 	select VBOOT_SAVE_RECOVERY_REASON_ON_REBOOT
+	select VBOOT_VBNV_CMOS
+	select VBOOT_VBNV_CMOS_BACKUP_TO_FLASH
 
 config UDELAY_LAPIC_FIXED_FSB
 	int

src/soc/amd/stoneyridge/Makefile.inc

@@ -49,6 +49,7 @@ bootblock-y += sb_util.c
 bootblock-y += tsc_freq.c
 bootblock-y += southbridge.c
 bootblock-y += nb_util.c
+bootblock-$(CONFIG_SPI_FLASH) += spi.c
 
 romstage-y += BiosCallOuts.c
 romstage-y += i2c.c
@@ -67,6 +68,7 @@ romstage-$(CONFIG_STONEYRIDGE_UART) += uart.c
 romstage-y += tsc_freq.c
 romstage-y += southbridge.c
 romstage-y += nb_util.c
+romstage-$(CONFIG_SPI_FLASH) += spi.c
 
 verstage-y += gpio.c
 verstage-y += i2c.c
@@ -77,6 +79,7 @@ verstage-y += reset.c
 verstage-$(CONFIG_STONEYRIDGE_UART) += uart.c
 verstage-y += tsc_freq.c
 verstage-y += nb_util.c
+verstage-$(CONFIG_SPI_FLASH) += spi.c
 
 postcar-y += monotonic_timer.c
 postcar-$(CONFIG_STONEYRIDGE_UART) += uart.c