datapath-windows: Do not delete internal port on OID_SWITCH_NIC_DISCONNECT

datapath-windows: Do not delete internal port on OID_SWITCH_NIC_DISCONNECT

According to the microsoft doc:
https://docs.microsoft.com/en-us/windows-hardware/drivers/network/hyper-v-extensible-switch-port-and-network-adapter-states
Below OID request sequence is validation:
         OID_SWITCH_NIC_CONNECT -> OID_SWITCH_NIC_DISCONNECT
                  ^                           |
                  |                           V
         OID_SWITCH_NIC_CREATE  <- OID_SWITCH_NIC_DELETE

In above sequence, the windows extensible switch interface assumes the
OID_SWITCH_PORT_CREATE has issued and the port has been created
successfully. If delete the internal port in HvDisconnectNic(),
HvCreateNic() will fail when received OID_SWITCH_NIC_CREATE late because
there is no corresponding port.

Signed-off-by: Jinjun Gao <jinjung@vmware.com>
Signed-off-by: Alin Gabriel Serdean <aserdean@ovn.org>