x86: Enable SPI flash support for coreboot

Turn on SPI flash support and related commands.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/configs/coreboot.h

@@ -257,10 +257,16 @@
 /*-----------------------------------------------------------------------
  * FLASH configuration
  */
+#define CONFIG_ICH_SPI
+#define CONFIG_SPI_FLASH
+#define CONFIG_SPI_FLASH_MACRONIX
+#define CONFIG_SPI_FLASH_WINBOND
+#define CONFIG_SPI_FLASH_GIGADEVICE
 #define CONFIG_SYS_NO_FLASH
-#undef CONFIG_FLASH_CFI_DRIVER
-#define CONFIG_SYS_MAX_FLASH_SECT		1
-#define CONFIG_SYS_MAX_FLASH_BANKS		1
+#define CONFIG_CMD_SF
+#define CONFIG_CMD_SF_TEST
+#define CONFIG_CMD_SPI
+#define CONFIG_SPI
 
 /*-----------------------------------------------------------------------
  * Environment configuration