[Qemu-block] 2.3-rc0 ahci-test failure on ppc64

[John Snow]

Andreas brought this failure to my attention; it looks like PIO 
read/writes for nsectors > 1 for IDE or AHCI will fail on ppc64.

The failure is in the IDE core layer.

In a nutshell, we've never *actually* supported PIO r/w for nsectors > 
1, I just started testing it as a spec compliance item (and because it 
was easy to just swap out DMA with PIO commands in my test framework.)

It looks like my tests passing on LE are just an unfortunate coincidence.

I'll prepare some patches tomorrow.

Thanks,
--js