DMA register offsets, as well as IRQ, to children. Use direct
config. Use machine type/subtype to determine which devices are
present.
* Add support for the second SCSI controller on the Indigo2.
Based on mvme68k and Atari drivers for the same chipset with the
addition of bus_space support. Attempts have been made to seperate out the
machine dependent dma components and more work is required in this area.
Tested on SGI R4K Indy, but has little testing on other platforms.
