ide: remove IDE devices from /proc/ide/ before unregistering them

IDE devices need to be removed from /proc/ide/ _before_ being unregistered:

* Drop 'ide_hwif_t *hwif' argument from destroy_proc_ide_device()
  and use drive->hwif instead.

* Rename destroy_proc_ide_device() to ide_proc_unregister_device().

* Call ide_proc_unregister_device() in drive_release_dev().

* Remove no longer needed destroy_proc_ide_drives().

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