elog: Fix compilation with CONFIG_CHROMEOS enabled

On ChromeOS devices the ELOG section size and offset are
provided by the FMAP, rather than KConfig. Some upstream
refactoring broke compilation in that case.

Change-Id: I8b08daa327726218815855c7c2be45f44fcffeed
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/8700
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/src/drivers/elog/elog.c b/src/drivers/elog/elog.c
index 7701906..8bc8a07 100644
--- a/src/drivers/elog/elog.c
+++ b/src/drivers/elog/elog.c
@@ -37,7 +37,7 @@
 
 #include <vendorcode/google/chromeos/fmap.h>
 
-#if CONFIG_ELOG_FLASH_BASE == 0
+#if !IS_ENABLED(CONFIG_CHROMEOS) && CONFIG_ELOG_FLASH_BASE == 0
 #error "CONFIG_ELOG_FLASH_BASE is invalid"
 #endif
 #if CONFIG_ELOG_FULL_THRESHOLD >= CONFIG_ELOG_AREA_SIZE