It seems that publishing BSPs in the index and sending upstream patches to linux-yocto are part the Criteria of being a Yocto Project Participant.
From https://www.yoctoproject.org/ecosystem/participant-registration
Are all your publicly accessible layers listed in the OpenEmbedded Layers index (http://layers.openembedded.org)?
Committed to sending to the open source community any patches to OpenEmbedded-Core, BitBake and other Yocto Project layers.