net: phy: updated the initialization routine for LAN87xx

The new initialization sequence is the improvement to the existing init
routine. Init routine does soft reset, run init script and set
Hw_init. Added the new access_smi_poll_timeout() for polling smi
bank write.

Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>