net: Dump client type 'info network'

net: Dump client type 'info network'

Include the client type name into the output of 'info network'. The
result looks like this:

(qemu) info network
VLAN 0 devices:
  rtl8139.0: type=nic,model=rtl8139,macaddr=52:54:00:12:34:57
Devices not on any VLAN:
  virtio-net-pci.0: type=nic,model=virtio-net-pci,macaddr=52:54:00:12:34:56
   \ network1: type=tap,fd=5

CC: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>