chromebooks: Configure Chrome EC board names

For devices with Chrome EC, state the "board" name(s), so they're built
as part of the image.

A number of EC boards aren't supported in the Chrome EC master branch,
they're brought along but commented out, waiting for a port to master
in the Chrome EC code base.

Change-Id: Ic6ab821de55cf9b4e8b48fe5ebc603adeb8bb28b
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/13548
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/intel/strago/Kconfig

@@ -54,4 +54,9 @@ config VGA_BIOS_ID
 	  in soc/intel/braswell/Makefile.inc as 8086,22b1
 
 endif #GOP_SUPPORT
+
+config EC_GOOGLE_CHROMEEC_BOARDNAME
+	string
+	default "strago"
+
 endif # BOARD_INTEL_STRAGO