- Now reserves I/O ranges according to EISA specs (four 256 bytes
  regions instead of a single 4KB region).

- By default, do not try to probe the bus if the mainboard does not
  seems to support EISA (allow this behaviour to be changed through a
  command-line option).

- Use parent bridge device dma_mask as default for each discovered
  device.

- Allow devices to be enabled or disabled from the kernel command line
  (useful for non-x86 platforms where the firmware simply disable
  devices it doesn't know about...).