ceph: move CEPH_SUPER_MAGIC definition to magic.h

The uapi headers are missing the ceph definition. Move it there so
userland apps can ID cephfs.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
3 files changed