mfd: cros_ec: Zero BUILD_ macro

Defined out build macro used when compiling embedded controller
firmware.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

include/linux/mfd/cros_ec_commands.h

@@ -13,6 +13,11 @@
 #ifndef __CROS_EC_COMMANDS_H
 #define __CROS_EC_COMMANDS_H
 
+
+
+
+#define BUILD_ASSERT(_cond)
+
 /*
  * Current version of this protocol
  *