We cannot provide auto-generated unique or persistent namespace
identifiers (EUI64, NGUID, UUID) easily. Since 6.1, namespaces have been
assigned a generated EUI64 of the form "52:54:00:<namespace counter>".
This is will be unique within a QEMU instance, but not globally.

Revert that this is assigned automatically and immediately deprecate the
compatibility parameter. Users can opt-in to this with the
`eui64-default=on` device parameter or set it explicitly with
`eui64=UINT64`.

Cc: libvir-list@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>