Merge r269488 from head:

Merge r269488 from head:

  For reasons which are not clear, r254263 broke some PCMCIA and CardBus
  bridges in strange ways, either rendering them unable to detect
  insertion and removal events, or possibly unable to read from the
  device behind the bridge.

  This fixes at least one laptop, a Toshiba Tecra M5 with a Texas
  Instruments PCxx12 (d=0x8039 v=0c104c) bridge.  The very similar
  Tecra M9 has the same bridge, but worked fine without this change.

  The bridge chip has no I/O port BAR, and there is nothing in the spec
  to suggest I/O decoding should be enabled; however enabling it fixes
  the issue.  Add an XXX comment to this effect.

Discussed with:		jhb, imp

git-svn-id: svn://svn.freebsd.org/base/stable/10@271060 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f