Before calling init_hwif_default, ide_unregister gets lock ide_lock and
disables irq.  init_hwif_default calls ide_default_io_base which calls
pci_get_device and later pci_get_subsys tries to apply for semaphore
pci_bus_sem and goes to sleep.

Mostly, pci_get_device should be called when irq is turned on.

ide_default_io_base just needs find if list pci_devices is empty.
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Cc: Greg KH <greg@kroah.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>