ide: add /sys/bus/ide/devices/*/{model,firmware,serial} sysfs entries

Cc: Dan Kegel <dank@kegel.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Xavier Bestel <xavier.bestel@free.fr>
Cc: Andrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>