vboot: remove vboot_handoff step

Depthcharge no longer reads this data structure, and uses
the vboot workbuf in vboot_working_data instead.

Since vboot2 downstream migration is not yet completed, the
vboot2 -> vboot1 migration code is still required, but has
been relocated to depthcharge.

BUG=b:124141368, b:124192753
TEST=make clean && make runtests
BRANCH=none

Change-Id: I769abbff79695b38d11fb6a93c2b42f64d4bafde
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33535
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/security/vboot/vboot_loader.c

@@ -73,17 +73,6 @@ static void vboot_prepare(void)
 
 		car_set_var(vboot_executed, 1);
 	}
-
-	/*
-	 * Fill in vboot cbmem objects before moving to ramstage so all
-	 * downstream users have access to vboot results. This path only
-	 * applies to platforms employing VBOOT_STARTS_IN_ROMSTAGE because
-	 * cbmem comes online prior to vboot verification taking place. For
-	 * other platforms the vboot cbmem objects are initialized when
-	 * cbmem comes online.
-	 */
-	if (ENV_ROMSTAGE && CONFIG(VBOOT_STARTS_IN_ROMSTAGE))
-		vboot_fill_handoff();
 }
 
 static int vboot_locate(struct cbfs_props *props)