ide: remove ideprobe_init()

* Rename ide_device_add() to ide_device_add_all() and make it accept
  'u8 idx[MAX_HWIFS]' instead of 'u8 idx[4]' as an argument.

* Add ide_device_add() wrapper for ide_device_add_all().

* Convert ide_generic_init() to use ide_device_add_all().

* Remove no longer needed ideprobe_init().

There should be no functionality changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>