[BNX2]: Add 1-shot MSI handler for 5709.

The 5709 supports the one-shot MSI handler similar to some of the tg3
chips.  In this mode, the MSI disables itself automatically until it
is re-enabled at the end of NAPI poll.

Put the request_irq/free_irq logic in common procedures.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>