Add non-Virtex5 support for LL TEMAC driver

This patch adds support for using the LL TEMAC Ethernet driver on
non-Virtex 5 platforms by adding support for accessing the Soft DMA
registers as if they were memory mapped instead of solely through the
DCR's (available on the Virtex 5).

The patch also updates the driver so that it runs on the MicroBlaze.
The changes were tested on the PowerPC 440, PowerPC 405, and the
MicroBlaze platforms.

Signed-off-by: John Tyner <jtyner@cs.ucr.edu>
Signed-off-by: John Linn <john.linn@xilinx.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>