normally BIOSes assign io/mmio range to different HT links without
overlapping, even same node same link should get non overlapping
entries.

but Rafael L. Wysocki's buggy BIOS creates a link with overlapping
entries for mmio and io:

  node 0 link 0: io port [1000, ffffff]
  node 0 link 0: mmio [e0000000, efffffff]
  node 0 link 0: mmio [a0000, bffff]
  node 0 link 0: mmio [80000000, ffffffff]

try to merge them and we will get:

  bus: [00, ff] on node 0 link 0
  bus: 00 index 0 io port: [0, ffff]
  bus: 00 index 1 mmio: [80000000, fcffffffff]
  bus: 00 index 2 mmio: [a0000, bffff]

so later we will reduce the chance to assign used resource to
unassigned device.
Reported-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>