[TG3]: Refinements to new locking strategy.

1. Move tp->irq_sync = 0 to before the interrupt mailbox IO in
   tg3_enable_ints() so that the interrupt handler will always see
   irq_sync == 0 when interrupts are enabled.

2. Remove the tg3_enable_ints() call in tg3_reset_hw(). Interrupts are
   always enabled explicitly or through tg3_netif_start(). This is to
   prevent interrupts being enabled while poll is disabled.

3. Update trans_start with jiffies in tg3_netif_stop() to prevent false
   NETDEV WATCHDOG.

4. Pass in the proper irq_sync parameter to tg3_full_lock() depending on
   netif_running() in some of the ethtool set calls.

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