netvsc: enhance transmit select_queue

The netvsc select queue function was missing many of the flow caching
features that exist in default tx queue selection. Add the same
logic to remember queue based on socket and implement two level
mapping (like RSS).

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>