This patch adds the ethtool callbacks necessary to configure the
number of RSS queues.

The maximum number of queues is in accordance with the datasheets.
Signed-off-by: Laura Mihaela Vasilescu <laura.vasilescu@rosedu.org>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>