Add "build.sh live-image" support for hppa.

Confirmed on qemu-9.2.0.
XXX: there is something wrong in qemu esiop(4) SCSI emulation etc.

---
qemu-system-hppa -m 512 -machine B160L \
-drive file=NetBSD-10.99.12-hppa-live.img,media=disk,format=raw,if=none,id=disk0 \
-device lsi53c895a,id=scsi0 -device scsi-hd,bus=scsi0.0,drive=disk0 \
-device scsi-cd,bus=scsi0.0 -netdev user,id=net0 -device tulip,netdev=net0 \
-nographic

SeaBIOS PA-RISC 32-bit Firmware Version 17 (QEMU 9.2.0)

Duplex Console IO Dependent Code (IODC) revision 17