datapath-windows: Update OVS_SWITCH_CONTEXT: external and internal port

datapath-windows: Update OVS_SWITCH_CONTEXT: external and internal port

The fields externalVport and internalVport of the OVS_SWITCH_CONTEXT
struct are currently defined as PVOID. However, all over the code they
are used as POVS_VPORT_ENTRY. In order to improve clarity and reduce the
need for useless casts to POVS_VPORT_ENTRY, this patch changes the type
from PVOID to POVS_VPORT_ENTRY.

This patch does not cleanup the code that already uses casts to
POVS_VPORT_ENTRY. This cleanup can be done later on as well.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Co-authored-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Acked-by: Ankur Sharma <ankursharma@vmware.com>
Acked-by: Eitan Eliahu <eliahue@vmware.com>
Acked-by: Nithin Raju <nithin@vmware.com>
Tested-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>