ide-disk: use ATA_ERR

Make use of ATA_ERR instead of hard-coded value in idedisk_set_max_address()
and idedisk_read_native_max_address().

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