Change in coreboot[master]: util/scripts: Add script to update submodules

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Change subject: util/scripts: Add script to update submodules
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Patch Set 2: Verified+1

Build Successful

https://qa.coreboot.org/job/coreboot-gerrit/58197/ : SUCCESS

https://qa.coreboot.org/job/coreboot-checkpatch/13620/ : SUCCESS