vendorcode/google/chromeos: Only select ELOG if SPI_FLASH is available

ELOG requires SPI_FLASH, so don't bother selecting if if SPI_FLASH isn't
available.

Change-Id: I080ac47e74aba820c94409d4913647abee215076
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12661
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/vendorcode/google/chromeos/Kconfig

@@ -25,7 +25,7 @@ config CHROMEOS
 	select TPM_INIT_FAILURE_IS_FATAL if PC80_SYSTEM && LPC_TPM
 	select SKIP_TPM_STARTUP_ON_NORMAL_BOOT if PC80_SYSTEM && LPC_TPM
 	select BOOTMODE_STRAPS
-	select ELOG
+	select ELOG if SPI_FLASH
 	select COLLECT_TIMESTAMPS
 	select VBOOT_VERIFY_FIRMWARE
 	help