DMA via the Secondary Inbound window, for now. Will probably
need to revisit this at some point.
Require that the board-specific i80312 front-end slice off a
subregion for the memory controller before calling i80312_attach(),
and fix a bug in the IQ80310 front-end that caused the Secondary
Inbound window to be configured incorrectly.
just basic Inbound and Outbound window setup is done, PCI configuration
space access (not quite working yet), and I/O and Memory space routines
so far.
thorpej