[coreboot-gerrit] Change in coreboot[master]: payloads/external: Add STM build as a payload

[Benjamin Doron (Code Review)]

Benjamin Doron has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/44687 )

Change subject: payloads/external: Add STM build as a payload
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Patch Set 3:

Is the STM a fully-fledged payload now? If not, it should presumably continue to be located in security/intel/stm