fix(docker): coreboot 25.06 test script

Signed-off-by: AtomicFS <vojtech.vesely@9elements.com>

Author: AtomicFS

tests/test_coreboot.sh

@@ -16,7 +16,7 @@ git clone --branch "${VERIFICATION_TEST_COREBOOT_VERSION}" --depth 1 https://rev
 cd coreboot
 
 # Pull in all submodules
-git submodule update --init --recursive --checkout --depth 1
+git submodule update --init --depth 1 3rdparty/vboot
 
 # Make
 for PAYLOAD in "${PAYLOADS[@]}"; do