hppa: Use 44 bit physical addresses for PA-8700

This is in line with the PA-8700 specification which demands 44 bits.

However, this change breaks the SeaBIOS functional tests as the firmware
assumes 40 bit physical addresses.  Therefore, change the functional
tests to instead run on an A400 which has the expected physical address
space size.

Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Anton Johansson <anjo@rev.ng>
Message-ID: <20260305-hppa-c3600-v6-3-d51526e5269c@rev.ng>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>