Update vboot submodule to upstream main

Updating from commit id b38e3a63:
    cros_ec: Use boot mode to check if EC can be trusted

to commit id ccc56f4:
    vboot: add x86 SHA256 ext support

Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Change-Id: I4e170e84a12646386d3fd84ae97add6c19f23809
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55992
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

3rdparty/vboot

@@ -1 +1 @@
-Subproject commit b38e3a63a8b1d42fd707e4c23e71c3f3ed84e6ad
+Subproject commit ccc56f46c51fa9d0c2b3c086ace97c14fe887c32