Tools: hv: use full nlmsghdr in netlink_send

There is no need to have a nlmsghdr pointer to another temporary buffer.
Instead use a full struct nlmsghdr.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>