ide: sanitize ide*_pm_* enums

* Move ide*_pm_* enums from ide-io.c to <linux/ide.h>.

* idedisk_pm_* -> ide_pm_*

* ide_pm_state_* -> ide_pm_*

* No need to set ide_pm_* enums to the fixed values.

* Uppercase ide_pm_* enums.

* Fix/update comments.

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