* Use ATA_CMD_* defines instead of WIN_* ones.

While at it:

* EXABYTE_ENABLE_NEXT -> ATA_EXABYTE_ENABLE_NEST

* SETFEATURES_{EN,DIS}_WCACHE -> SETFEATURES_WC_{ON,OFF}

* SETFEATURES_{EN,DIS}_AAM -> SETFEATURES_AAM_{ON,OFF}

* SMART_* -> ATA_SMART_*

* Remove stale comment from ide-proc.c.

Partially based on earlier work by Chris Wedgwood.
Acked-by: Chris Wedgwood <cw@f00f.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>