chromeos: vboot-related functions move to common vboot code

This moves a few vboot-prefixed functions that were defined in chromeos.c to
vboot_common.c, since those are only relevant to vboot and depend on the vboot
handoff data. This allows more separation between CONFIG_CHROMEOS and what
CONFIG_CHROMEOS selects, so that each separate option (such as
CONFIG_VBOOT_VERIFY_FIRMWARE) can be enabled separately.

Thus, the actual definitions of these functions will only be declared when
CONFIG_VBOOT_VERIFY_FIRMWARE is set, so the check before calling
vboot_skip_display_init in bootmode was also adapted.

Change-Id: I52f8a408645566dac0a2100e819c8ed5d3d88ea5
Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Reviewed-on: http://review.coreboot.org/11497
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/vendorcode/google/chromeos/vboot_common.h b/src/vendorcode/google/chromeos/vboot_common.h
index 088cd1e..f4d5e11 100644
--- a/src/vendorcode/google/chromeos/vboot_common.h
+++ b/src/vendorcode/google/chromeos/vboot_common.h
@@ -39,5 +39,13 @@
 /* The following functions return 0 on success, < 0 on error. */
 int vboot_named_region_device(const char *name, struct region_device *rdev);
 int vboot_region_device(const struct region *reg, struct region_device *rdev);
+int vboot_get_handoff_info(void **addr, uint32_t *size);
+
+/* The following functions return 1 for true and 0 for false. */
+int vboot_skip_display_init(void);
+int vboot_enable_recovery(void);
+int vboot_enable_developer(void);
+
+void vboot_reboot(void);
 
 #endif /* VBOOT_COMMON_H */