sh: smsc911x support for the rsk7203 board

This patch adds support for the LAN9118 ethernet on rsk7203.

The LAN9118 controller is hooked up using a 16-bit data bus,
but the rsk7203 board does not swap the byte lanes as needed
between the sh7203 processor and the the ethernet controller.

In the processor the CS memory window is configured in 16-bit
mode but the smsc911x driver is told to do 32-bit accesses to
improve performance. The SMSC911X_SWAP_FIFO flag is used
to tell the driver to do software byte swapping of fifo data.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>