S2IO: Optimized the delay to wait for command completion

- Optimized delay to wait for command completion so as to reduce the
  initialization wait time.
- Disable differentiated services steering. By default RMAC is configured to
  steer traffic with certain DS codes to other queues. Driver must initialize
  the DS memory to 0 to make sure that DS steering will not be used by default.

Signed-off-by: Sivakumar Subramani <sivakumar.subramani@neterion.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>