arch/ppc/qemu: Add parse hex words for compatibility with Apple OF

Apple OF has parse-1hex, parse-2hex, parse-3hex words that may be used
by FCode ROMs so add these for compatibility

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>