vsock/virtio: add support for device suspend/resume

vsock/virtio: add support for device suspend/resume

[ Upstream commit bd50c5dc182b0a52599f87b429f9a5a9cbfc9b1c ]

Implement .freeze and .restore callbacks of struct virtio_driver
to support device suspend/resume.

During suspension all connected sockets are reset and VQs deleted.
During resume the VQs are re-initialized.

Reported by: Vilas R K <vilas.r.k@intel.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 53b08c498515 ("vsock/virtio: initialize the_virtio_vsock before using VQs")
Signed-off-by: Sasha Levin <sashal@kernel.org>