ARM: dove: use fixed PCI i/o mapping

The i/o regions are changed from 1MB to 64KB. It's likely that the 2nd
bus is not setup correctly.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>