enic: Enable support for multiple hardware receive queues

This patch enables support for multiple receive queues. If multiple receive
queues are used ingress traffic is hashed into one of the receive queues based
on IP or TCP or both headers. The max number of supported receive queues per
vnic is 8.

Signed-off-by: Neel Patel <neepatel@cisco.com>
Signed-off-by: Christian Benvenuti <benve@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: Nishank Trivedi <nistrive@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>