ide: replace special_t typedef by IDE_SFLAG_* flags

Replace:
- special_t typedef by IDE_SFLAG_* flags
- 'special_t special' ide_drive_t's field by 'u8 special_flags' one

There should be no functional changes caused by this patch.

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