ide: remove ata_nsector_t, ata_data_t and atapi_bcount_t

Remove ata_nsector_t, ata_data_t (unused) and atapi_bcount_t.

While at it:
* replace 'HWIF(drive)' by 'hwif'

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>