hw/hppa/machine: Map the PDC memory region with higher priority

hw/hppa/machine: Map the PDC memory region with higher priority

The region in range [0xf0000000 - 0xf1000000] is the PDC area
(Processor Dependent Code), where the firmware is loaded.
This region has higher priority than the main memory.

When the machine has more than 3840MB of RAM, there is an
overlap. Since the PDC is closer to the CPU in the bus
hierarchy, it gets accessed first, and the CPU does not have
access to the RAM in this range.

To model the same behavior and keep a simple memory layout,
reduce the priority of the RAM region. The PDC region ends
overlapping the RAM.

Acked-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200109000525.24744-4-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>