Update vboot submodule to upstream master

Updating from commit id 6ef33b99:
2019-11-22 Hung-Te Lin     futility: updater: refactor: unify
                           getting temp files for firmware images

to commit id 0e97e25e:
2020-01-23 Julius Werner   2lib: Fix struct vb2_hash the way it was
			   meant to be

Change-Id: I539aba2f283804f67ff3ff4f98324b3d10b2bb54
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38604
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Joel Kitching <kitching@google.com>

3rdparty/vboot

@@ -1 +1 @@
-Subproject commit f5367d598a985520a8c935f68ac90d295c7b8d8e
+Subproject commit 0e97e25e85f0499e23b09a31a2c7116759f191d5