delkin_cb: add PM support

* Factor out chipset initialization code from delkin_cb_probe()
  to delkin_cb_init_chipset().

* Assign ->init_chipset in struct delkin_cb_port_info.

* Add delkin_cb_{suspend,resume}() (->suspend/->resume methods).

Fixes kernel bugzilla bug #11735:

http://bugzilla.kernel.org/show_bug.cgi?id=11735

Tested-by:  <bumble.bee@xs4all.nl>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>