[ARM] 4341/1: iop13xx: fix i/o address translation

PCI devices were being programmed with an incorrect base address value.
This patch moves I/O space into a 16-bit addressable region and corrects
the i/o offset.

Much thanks to Martin Michlmayr for tracking this issue and testing
debug patches.

Cc: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>