[PATCH] ARM: 2792/1: IXP4xx iomap API implementation

Patch from Deepak Saxena

This patch implements the iomap API for Intel IXP4xx NPU systems.
We need to implement our own version of the API functions b/c of the
PCI hostbridge does not provide the capability to map PCI I/O space
into the CPU's physical memory space. In addition, if a system has
more than 64M of PCI memory mapped BARs, PCI memory must also be
accessed indirectly.  This patch changes the assignment of PCI I/O
resources to fall into to 0x0000:0xffff range so that we can trap
I/O areas in our ioread/iowrite macros.

Signed-off-by: Deepak Saxena
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>