S2io: Multiqueue network device support implementation

S2io: Multiqueue network device support implementation

- Resubmit #3
Multiqueue netwrok device support implementation.
- Added a loadable parameter "multiq" to enable/disable multiqueue support,
  by default it is disabled.
- skb->queue_mapping is not used for queue/fifo selection. FIFO selection is
  based on skb->priority.
- Added per FIFO flags FIFO_QUEUE_START and FIFO_QUEUE_STOP. Check this flag
  for starting and stopping netif queue and update the flags accordingly.
- In tx_intr_handler added a check to ensure that we have free TXDs before wak-
  ing up the queue.
- Added helper functions for queue manipulation(start/stop/wakeup) to invoke
  appropriate netif_ functions.
- Calling netif_start/stop for link up/down case respectively.

- As per Andi kleen's review comments, using skb->priority field for FIFO
  selection.

Signed-off-by: Surjit Reang <surjit.reang@neterion.com>
Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>