chromeos: rename for easier patch merging

In order to more cleanly apply upcoming changes some files
will need to do a dance.

Change-Id: Ib50670743c10221785447490190ecdbff8c764fe
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8654
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

src/vendorcode/google/chromeos/Makefile.inc

@@ -38,8 +38,8 @@ CFLAGS_common += -DMOCK_TPM=0
 endif
 
 ifeq ($(CONFIG_VBOOT_VERIFY_FIRMWARE),y)
-romstage-y += vboot_handoff.c
-ramstage-y += vboot_handoff.c
+romstage-y += vboot_helper.c
+ramstage-y += vboot_helper.c
 romstage-y += vboot_loader.c
 rmodules_$(ARCH-romstage-y)-y += vboot_wrapper.c