tg3: ethtool phys_id default

When asked to blink LEDs the tg3 driver behaves when using:
	ethtool -p ethX
The default value for data is zero, and other drivers interpret this
as blink forever (or at least a really long time).  The tg3 driver
interprets this as blink once.  All drivers should have the same
behaviour.

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