ide: add ide_dump_identify() debug helper

* Add ide_dump_identify() debug helper for dumping raw identify data in
  the hdparm friendly format (== the identify data can be extracted from
  dmesg output and passed to hdparm --Istdin).

* Dump identify data in ide-probe.c::do_identify() if DEBUG is enabled.

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