smsc95xx: configure LED outputs

SMSC LAN9500 has dual purpose GPIO/LED pins, and by default at power-on
these are configured as GPIOs.  This means that if LEDs are fitted they
won't ever light.

This patch sets them to be LED outputs for speed, duplex and
link/activity.

Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>