ide: mark "ide=reverse" option as obsolete

- it is valid only if "Probe IDE PCI devices in the PCI bus order
  (DEPRECATED)" config option is used

- Greg needs to remove pci_get_device_reverse() for PCI core changes

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>