xsysace: make it 'struct hd_driveid'-free

* Change cf_id field in struct ace_device from 'struct hd_driveid *id'
  to 'u16 *id' and update driver accordingly.

* Include <linux/ata.h> directly instead of through <linux/hdreg.h>.

While at it:

* Use ata_id_u32() macro.

There should be no functional changes caused by this patch.

Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>