userns: Convert __dev_set_promiscuity to use kuids in audit logs

Cc: Klaus Heinrich Kiwi <klausk@br.ibm.com>
Cc: Eric Paris <eparis@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>