datapath-windows: add netlink message parsing APIs

In this change we introduce Netlink.c, Netlink.h and NetlinkProto.h
in datapath-windows. These files will provide netlink message
data structures and parsing APIs.

Changes are on similar lines to userspace netlink code.

We have mapped the userspace APIs and data structures to
kernel coding convention.
for example:
nlmsghdr ==> NL_MSG_HDR
nl_attr_get ==> NlAttrGet

Signed-off-by: Ankur Sharma <ankursharma@vmware.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/18
Acked-by: Nithin Raju <nithin@vmware.com>
Acked-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath-windows: Using windows kernel netlink parsing APIs.

In this patch we incorporate the usage of netlink message
and the parsing APIs that were added in previous commit.

Signed-off-by: Ankur Sharma <ankursharma@vmware.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/18
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
datapath-windows: remove reference to OvsNetlink.h

In this patch we remove reference to OvsNetlink.h.
Since we do not refer to lib/netlink-protocol.h anymore,
hence removed the WIN_DP based check as well.

Signed-off-by: Ankur Sharma <ankursharma@vmware.com>
Reported-at: https://github.com/openvswitch/ovs-issues/issues/18
Acked-by: Nithin Raju <nithin@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>