vhost-vsock: add VIRTIO_F_RING_PACKED to feature_bits

vhost-vsock: add VIRTIO_F_RING_PACKED to feature_bits

Not having VIRTIO_F_RING_PACKED in feature_bits[] is a problem when the
vhost-vsock device does not offer the feature bit VIRTIO_F_RING_PACKED
but the in QEMU device is configured to try to use the packed layout
(the virtio property "packed" is on).

As of today, the  Linux kernel vhost-vsock device does not support the
packed queue layout (as vhost does not support packed), and does not
offer VIRTIO_F_RING_PACKED. Thus when for example a vhost-vsock-ccw is
used with packed=on, VIRTIO_F_RING_PACKED ends up being negotiated,
despite the fact that the device does not actually support it, and
one gets to keep the pieces.

Fixes: 74b3e46630 ("virtio: add property to enable packed virtqueue")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Message-Id: <20240429113334.2454197-1-pasic@linux.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>