bitbake.conf: Enable ipv6/acl/xattr for nativesdk

bitbake.conf: Enable ipv6/acl/xattr for nativesdk

I was surprised to realise our buildtools doesn't support IPv6 which breaks
usage in our own autobuilder, let alone anywhere else.

Enable ipv6 in our SDKs and enable acl/xattr as well before we have the same
kind of issues with those, these features are now common on most linux systems
and we should be defaulting to including them.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>