NET: au1000_eth: Pass MACDMA address through platform resource info.

This patch removes the last hardcoded base address from the au1000_eth
driver.  The base address of the MACDMA unit was derived from the
platform device id; if someone registered the MACs in inverse order
both would not work.
So instead pass the base address of the DMA unit to the driver with
the other platform resource information.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
Acked-by: David S. Miller <davem@davemloft.net>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2674/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>