soc/intel/skylake: use SPI flash boot_device_rw() for ealy stages

If the boot device is SPI flash use the common one in the
early stages. While tweaking the config don't auto select
SPI_FLASH as that is handled automatically by the rest of the
build system.

BUG=chrome-os-partner:56151

Change-Id: Ifd51a80fd008c336233d6e460c354190fcc0ef22
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/16202
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
diff --git a/src/soc/intel/skylake/Kconfig b/src/soc/intel/skylake/Kconfig
index a61774f..7fa129b 100644
--- a/src/soc/intel/skylake/Kconfig
+++ b/src/soc/intel/skylake/Kconfig
@@ -13,6 +13,7 @@
 	select ARCH_ROMSTAGE_X86_32
 	select ARCH_VERSTAGE_X86_32
 	select ACPI_NHLT
+	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select CACHE_MRC_SETTINGS
 	select CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM if RELOCATABLE_RAMSTAGE
@@ -46,7 +47,6 @@
 	select SOC_INTEL_COMMON_RESET
 	select SMM_TSEG
 	select SMP
-	select SPI_FLASH
 	select SSE2
 	select SUPPORT_CPU_UCODE_IN_CBFS
 	select TSC_CONSTANT_RATE