hw/arm/virt: Silence dtc /intc warnings

hw/arm/virt: Silence dtc /intc warnings

When running dtc on the guest /proc/device-tree we get the
following warnings: "Warning (unit_address_vs_reg): Node <name>
has a reg or ranges property, but no unit name", with name:
/intc, /intc/its, /intc/v2m.

Nodes should have a name in the form <name>[@<unit-address>] where
unit-address is the primary address used to access the device, listed
in the node's reg property. This fix seems to make dtc happy.

Signed-off-by: Eric Auger <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Message-id: 1530044492[email protected]
Signed-off-by: Peter Maydell <[email protected]>