parisc: Increase SEABIOS_HPPA_VERSION to version 2

This version adds fixes which allow choosing the primary boot device.

Either via qemu bootindex parameter, e.g.:
 -device scsi-hd,drive=drive1,bus=scsi0.0,channel=0,scsi-id=6,lun=0,bootindex=1
 -drive file=image.img,if=none,id=drive1

or via qemu boot order option to select the SCSI ID, e.g.:
 -boot order=g-m: machine implementation dependent drives (SCSI ID)
where "g" means SCSI ID 0, "h" is SCSI ID 1 and so on.

Signed-off-by: Helge Deller <deller@gmx.de>