[ARM] 3349/1: ixp4xx exp bus defines

Patch from Alessandro Zummo

This patch adds a few defines that are useful
to configure the CS regions on ixp4xx.

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: OEyvind Repvik <oyvind@repvik.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>