ide: remove drive->driveid

* Factor out HDIO_[OBSOLETE,GET]_IDENTITY ioctls handling
  to ide_get_identity_ioctl().

* Use temporary buffer in ide_get_identity_ioctl() instead
  of accessing drive->id directly.

* Add ide_id_to_hd_driveid() inline to convert raw id into
  struct hd_driveid format (needed on big-endian).

* Use ide_id_to_hd_driveid() in ide_get_identity_ioctl(),
  cleanup ide_fix_driveid() and switch ide to use use raw id.

* Remove no longer needed drive->driveid.

  This leaves us with 3 users of struct hd_driveid in tree:
  - arch/um/drivers/ubd_kern.c
  - drivers/block/xsysace.c
  - drivers/usb/storage/isd200.c

While at it:

* Use ata_id_u{32,64}() and ata_id_has_{dma,lba,iordy}() macros.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>