ARM: DaVinci: various EMAC driver locking and race fixes

1)Cleanup/removal of Rx_Multipacket_complete_notify which featured
potential race condition if emac_poll() is re-entered
2)Extension of tx-spinlock to encompass Tx_complete_notifications(as
completion entries are stored in a global array)
3) KGDB Fix: modify emac_poll() to invoke netif_rx_complete  only if
device resides on poll list. With emac_poll() also being called from
netpoll_poll(), its possible that emac_poll() is invoked when the device
has not been added to the polling list with netif_rx_schedule()
4)Modified all spin_lock_irq to spin_Lock_irqsave so that flags are
restored properly
Signed-off-by: Kevin Hilman <khilman@mvista.com>