hw/hppa/machine: Load 64-bit firmware on 64-bit machines

hw/hppa/machine: Load 64-bit firmware on 64-bit machines

Load the 64-bit SeaBIOS-hppa firmware by default when running on a 64-bit
machine. This will enable us to later support more than 4GB of RAM and is
required that the OS (or PALO bootloader) will start or install a 64-bit kernel
instead of a 32-bit kernel.

Note that SeaBIOS-hppa v16 provides the "-fw_cfg opt/OS64,string=3" option with
which the user can control what the firmware shall report back to the OS:
Support of 32-bit OS, support of a 64-bit OS, or support for both (default).

Wrap firmware loading inside !qtest_enabled() to avoid this warning with
qtest: "qemu-system-hppa: no firmware provided".

Signed-off-by: Helge Deller <deller@gmx.de>
Acked-by: Richard Henderson <richard.henderson@linaro.org>