[ARM] 4318/2: DSM-G600 Board Support

This patch adds support for the D-Link DSM-G600 Rev A.
This is an ARM XScale IXP4xx system relatively similar to
the NSLU2 and NAS-100D already supported by mainline. An
important difference is Gigabit Ethernet support using
the Via Velocity chipset.

This patch is the combined work of Michael Westerhof and
Alessandro Zummo, with contributions from Michael-Luke
Jones. This version addresses review comments from rmk
and Deepak Saxena.

Signed-off-by: Michael-Luke Jones <mlj28@cam.ac.uk>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Michael Westerhof <mwester@dls.net>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>