ht6560b: force prefetch for some devices

Prefetch needs to be set for some ide devices to work when connected to
a ht6560b interface. This was not always done properly, causing a system
with a HD and CD on the primary interface to not work properly. Or, in
effect, hang hard.

This patch forces prefetch on devices before checking whether it
is necessary to change the settings in the interface

This patch should also be applied to 2.4. I don't currently have a
2.4 tree around.

(also change my email address)

Signed-off-by: Jan Evert van Grootheest <janevert@caiway.nl>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>