OEM i2c over IPMI

[Patrick Venture]

We have a linux kernel driver for i2c-via-ipmi that ties into
https://gerrit.openbmc-project.xyz/12604 - I'm putting this upstream
but since it's an IPMI OEM handler, it can nicely go into its own
repository - I was curious if there was any OpenBMC interest?  If so,
we can aim for the phosphor namespace, otherwise I'll just ask that it
be pushed into a google repo.

Thoughts?
Patrick