enic: Add support for multiple hardware receive queues

Add support for multiple hardware receive queues. The ingress traffic is hashed into one of the receive queues based on IP or TCP or both headers. The max no. of receive queues supported is 8.

Signed-off-by: Vasanthy Kolluri <vkolluri@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: David Wang <dwang2@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>