chromebooks: Define GBB hardware IDs

This makes the test IDs the default, taken from depthcharge
master (board/*/fmap.dts, hwid property).

Change-Id: I25793962ac16f451f204dbba6ede6a64c847cfd5
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/13634
Reviewed-by: Martin Roth <martinroth@google.com>
Tested-by: build bot (Jenkins)

src/mainboard/intel/strago/Kconfig

@@ -59,4 +59,8 @@ config EC_GOOGLE_CHROMEEC_BOARDNAME
 	string
 	default "strago"
 
+config GBB_HWID
+	string
+	depends on CHROMEOS
+	default "STRAGO TEST A-A 9657"
 endif # BOARD_INTEL_STRAGO