This patch adds sockmap support for vsock sockets. It is intended to be
usable by all transports, but only the virtio and loopback transports
are implemented.

SOCK_STREAM, SOCK_DGRAM, and SOCK_SEQPACKET are all supported.
Signed-off-by: NBobby Eshleman <bobby.eshleman@bytedance.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>