Assign correct address type to spapr-vlan and spapr-vty.

Assign correct address type to spapr-vlan and spapr-vty.

For pseries guest, spapr-vlan and spapr-vty is based
on spapr-vio address. According to model of network
device, the address type should be assigned automatically.
For serial device, serial pty device is recognized as
spapr-vty device, which is also on spapr-vio.

So this patch is to correct the address type of
spapr-vlan and spapr-vty, and build correct
command line of spapr-vty.

Signed-off-by: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Reviewed-by:   Michael Ellerman<michaele@au1.ibm.com>