ChromeOS: Add legacy mainboard_ec_running_ro()

Motivation is to have mainboard_chromeos_acpi_generate()
do nothing else than fill ACPI \OIPG package.

Change-Id: I3cb95268424dc27f8c1e26b3d34eff1a7b8eab7f
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58896
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/bootmode.h

@@ -3,6 +3,8 @@
 #ifndef __BOOTMODE_H__
 #define __BOOTMODE_H__
 
+#include <stdbool.h>
+
 /* functions implemented per mainboard: */
 void init_bootmode_straps(void);
 int get_write_protect_state(void);
@@ -12,6 +14,7 @@ int clear_recovery_mode_switch(void);
 int get_wipeout_mode_switch(void);
 int get_lid_switch(void);
 int get_ec_is_trusted(void);
+bool mainboard_ec_running_ro(void);
 
 /* Return 1 if display initialization is required. 0 if not. */
 int display_init_required(void);