IDE controllers, which are more-or-less compatible with the
AMD controllers.
XXX Need to determine the correct timing value for the nForce2
XXX at Ultra133, so we cap it at Ultra100, for now.
disable multiword DMA for these chips. multiword DMA can be forced with
options PCIIDE_AMD756_ENABLEDMA on rev D2 chips, but use at your own risk !
While I'm there remove a duplicate allocation of sc_wdcdev.nchannels in HPT
code.