sys/cddl: Convert 'struct vop_vector' to 'struct vop_ops' type

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
sys/cddl: Fix member name of struct as 's/v_op/v_ops/'

Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>