ppc64le support in multi-arch image

[harche]

The multi-arch image for docker registry, https://hub.docker.com/_/registry, doesn't have the reference to ppc64le image.

We will like to add the support for ppc64le architecture as well for this image.

[clnperez]

Can you submit a patch to the official images repo to add it?

https://github.com/docker-library/official-images/blob/master/library/registry