ide: add proper PCI PM support (v2)

* Keep pointer to ->init_chipset method also in
  struct ide_host and set it in ide_host_alloc_all().

* Add ide_pci_suspend() and ide_pci_resume() helpers
  (default ->suspend and ->resume implementations).

* ->init_chipset can no longer be marked __devinit.

* Add proper PCI PM support to IDE PCI host drivers
  (rz1000.c and tc86c001.c are skipped for now since
  they need to be converted from using ->init_hwif
  to use ->init_chipset instead).

v2:
* Cleanup CONFIG_PM #ifdef-s per akpm's suggestion.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>