qlge: Move TX completions from workqueue to NAPI.

TX completions were running in a workqueue queued by the ISR.  This
patch moves the processing of TX completions to an existing RSS NAPI
context.
Now each irq vector runs NAPI for one RSS ring and one or more TX
completion rings.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>