common: kernel-resin: enable user namespacing
common: kernel-resin: enable user namespacing

Enable CONFIG_USER_NS, a kernel feature used for user namespacing, and
required for docker-in-docker.

Change-type: patch
Signed-off-by: Joseph Kogut <461476587780aa9fa5611ea6dc3912c146a91760@balena.io>
resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin,resin-os/meta-resin