bnx2x: switch to napi_complete_done()

Switch from napi_complete() to napi_complete_done()
for better GRO support (gro_flush_timeout) and core NAPI
features.

Do not rearm interrupts if we are busy polling,
to reduce bus and interrupts overhead.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Adam Belay <abelay@google.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Yuval Mintz <Yuval.Mintz@cavium.com>
Cc: Ariel Elior <ariel.elior@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>