qlcnic: Set real_num_{tx|rx}_queues properly

Do not set netdev->real_num_tx_queues directly,
let netif_set_real_num_tx_queues() take care of it.
Do not overwrite netdev->num_tx_queues everytime when driver
changes its Tx ring size through ethtool -L and also notify
stack to update number of Rx queues.

Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>