aab5efa574
space handles to describe the task file registers, aux register, 16 bit data register and 32 bit data register. The wdc softc structure has been moved to a separate file. Added support for multiple attachments by separating the core of the probe and attach functions from the mainbus probe and attach routines. Added a new wdc flags 32_BIT so that the wd can determine 32 bit xfer support from the wdc device.