chromeos: fix some compilation issues

This fixes some compilation issues observed with CONFIG_CHROMEOS.
Nothing within the vbootX subdirectories is functional yet, but
a partial compilation within the chromeos direction works now.
Notable fixes: duplicate definitions and missing prototypes.

Change-Id: I53c7b6dcf06b8bcf41a8555094b48968c0740026
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9936
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/vendorcode/google/chromeos/chromeos.h

@@ -23,9 +23,14 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <bootmode.h>
+#include <rules.h>
 #include "vboot_common.h"
 #include "vboot2/misc.h"
 
+#if ENV_ROMSTAGE
+void save_chromeos_gpios(void);
+#endif
+
 /* functions implemented in vbnv.c: */
 int get_recovery_mode_from_vbnv(void);
 int vboot_wants_oprom(void);