elog: enable by default for CHROMEOS

elog breaks the build if ELOG_FLASH_BASE isn't configured -
and CHROMEOS isn't enabled, since with Chrome OS builds, it
just uses fmap to find out the base.

So it makes sense to enable it on all Chrome OS builds - if
the code never uses it, the linker will drop it soon enough.

Change-Id: I7ee129fadf75caf15fb9bd32b0acf6f7d9d015d8
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/9965
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/vendorcode/google/chromeos/Kconfig

@@ -27,6 +27,7 @@ config CHROMEOS
 	default n
 	select TPM
 	select BOOTMODE_STRAPS
+	select ELOG
 	help
 	  Enable ChromeOS specific features like the GPIO sub table in
 	  the coreboot table. NOTE: Enabling this option on an unsupported