af_vsock: update comments for stream sockets

Replace 'stream' to 'connection oriented' in comments as
SEQPACKET is also connection oriented.

Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>